AISI P20 | AISI P20+Ni | AISI P20+S Forging Parts | China Professional Forging Manufacturer

About Our AISI P20 Series Forging Parts

Established in 1997, Jiangsu Liangyi Co.,Limited is a professional ISO 9001:2015 certified manufacturer and supplier of AISI P20, AISI P20+Ni, and AISI P20+S open die forging parts and seamless rolled steel forged rings, based in Jiangyin City, Jiangsu Province, China. With state-of-the-art forging and inspection facilities, we produce custom AISI P20 forged components ranging from 30KGS to 30,000KGS, with an annual production capacity of 120,000 tons, fully compliant with ASTM, AISI, DIN, EN, and JIS international standards.

Unlike distributors or trading companies, every AISI P20 forging part we supply is produced entirely within our own 80,000 m² facility in Jiangyin — from raw steel melting and open die forging through to heat treatment, NDT inspection, and precision machining. This single-source manufacturing model is how we maintain tighter dimensional tolerances, more consistent metallurgical quality, and faster response times than multi-tier supply chains, and it is why global mold makers, automotive tooling manufacturers, and precision engineering companies in over 50 countries choose Jiangsu Liangyi as their long-term AISI P20 forging partner.

Official dedicated product page: https://www.jnmtforgedparts.com/AISI-P20-forging-parts.html

Full Range of AISI P20 Series Forged Steel Products

We manufacture a complete line of AISI P20 series forged shapes entirely from our Jiangyin factory — no subcontracting, no third-party heat treatment, no re-rolled material sold as forging. Every shape listed below is open die forged or ring rolled from certified AISI P20 series steel billet under our direct process control, then heat treated and inspected on-site before shipment. Standard and custom dimensions are both available. Contact us with your drawing or technical requirement for a factory-direct quotation.

AISI P20 Forged Round Bars, Flat Bars & Shafts

Our AISI P20 forged bars are produced by open die forging from pre-certified billets, ensuring a refined, directional grain structure that provides higher fatigue resistance and better through-hardness uniformity compared to rolled bar products. Available steel grades include standard AISI P20, nickel-enhanced AISI P20+Ni, and free-machining AISI P20+S.

AISI P20 Seamless Rolled Rings & Gear Rings

Our AISI P20 seamless rolled rings are produced by a dedicated ring rolling mill — not by bending and welding bar or plate, which produces inconsistent grain orientation and weld zone weaknesses. True seamless ring rolling creates a continuous, wrap-around grain structure that maximizes hoop strength and fatigue resistance, which is critical for mold frames, die holders, and annular tooling components under cyclic load.

AISI P20 Forged Hollow Bars, Sleeves, Bushes & Pipes

Forged hollow bars and sleeves are produced by piercing and elongation of solid forgings, delivering a fully wrought, inclusion-free bore surface and superior internal integrity compared to machined-from-solid round bars for thick-walled applications. Commonly specified for injection mold barrel inserts, die casting shot sleeves, and heavy-duty mold frame components.

• AISI P20+Ni forged hubs, housings, shells, sleeves, bushes, casings and hollow bars — OD up to Ø 1,500 mm, bore Ø 80–900 mm
• AISI P20+S forged sleeves, pipes, barrels and tubing for die casting tooling and injection machine components
• AISI P20 forged pipes, tubes, casings and housings for plastic mold components and structural tooling

AISI P20 Forged Blocks, Plates & Discs

Large forged blocks and plates in AISI P20 series steels are among our highest-volume products, as they form the core cavity inserts and mold base plates for large-scale injection molds. Our open die forging process produces a uniformly refined, banded-free microstructure throughout the full cross-section of even our largest blocks — something that is impossible to achieve with cast or lightly hot-rolled plate products.

• AISI P20+Ni forged discs, blocks and die blocks — max single piece weight 30,000 KGS; max width 2,000 mm × thickness 800 mm
• AISI P20 forged plates — custom dimensions, standard forging tolerance to DIN 7527 Part 6 or ASTM A788
• Surface finish options: as-forged, rough machined, or semi-finish machined to your drawing

Why AISI P20 Forging Is Superior to Rolled Bar or Cast Plate

Not all AISI P20 steel products are equal. The same chemical composition can result in dramatically different mechanical performance depending on how the steel was processed — forged, rolled, or cast. As a factory that has produced open die forgings exclusively for 25+ years, we see buyers make costly mistakes by substituting rolled plate or continuous cast material into mold applications that require true forged quality. Here is why forging is the correct choice for demanding P20 applications:

For mold bases up to ~200 mm thick and low production run molds where cost is the primary driver, AISI P20 rolled plate may be acceptable. However, for cavity inserts deeper than 300 mm, large injection molds with projected cavity pressure over 100 MPa, zinc die casting tooling requiring 500,000+ cycle life, or any application where an internal defect causing mold cracking or premature failure would be commercially unacceptable — forged AISI P20 is the only technically appropriate choice. All Jiangsu Liangyi AISI P20 products are true open die forgings with full forging reduction documentation available on request.

AISI P20 Series Steel: Metallurgical Overview & Grade Selection Guide

AISI P20 belongs to the P-series (mold steels) of the AISI tool steel classification system — a family of low-carbon, low-alloy steels specifically designed to be readily machinable in the annealed condition and then case hardened or surface treated in service. However, modern industrial use of AISI P20 — particularly in the forged product form — has evolved far beyond its original case-hardening intent. Today, AISI P20 is predominantly supplied in the pre-hardened and tempered condition at approximately Brinell 280–320 HB (Rockwell ~29–33 HRC), eliminating the need for heat treatment by the mold maker and dramatically reducing the risk of distortion in large, precision-machined mold cavities.

The performance of AISI P20 is essentially based on the chrome-molybdenum (Cr-Mo) alloying system. The chromium content (1.4-2.0%) provides the hardenability depth required for uniform hardness in thick sections, improves resistance to softening at elevated service temperatures and contributes to the fine carbide network that gives excellent polishability. Molybdenum at 0.30–0.55% suppresses temper embrittlement — a phenomenon where certain alloy steels lose toughness when slow-cooled through the 250–400°C range — while simultaneously strengthening the ferrite matrix and improving creep resistance. This makes Mo an indispensable element in steels intended for the prolonged, cyclic thermal exposure of injection mold service.

AISI P20 vs AISI P20+Ni vs AISI P20+S: How to Choose the Right Grade

The three grades in the P20 series each address a specific engineering need. The following table and guide will help you select the optimal grade for your application before requesting a quotation:

We also supply a full range of alternative forging steel materials including AISI H13, AISI 420, P21, NAK80-equivalent grades, carbon steels, and low-alloy structural steels for various industrial applications beyond mold making.

AISI P20 vs Other Common Mold Steels: When to Use Which

AISI P20 is the world's most widely used plastic injection mold steel by volume, but it is not always the optimal choice for every application. Global mold makers frequently ask us to help them decide between AISI P20 and alternative tool steels when designing new molds. Based on over 25 years of forging experience serving the mold industry across 50+ countries, here is our practical comparison:

Our practical guidance: for the vast majority of thermoplastic injection molds — including almost all automotive interior trim, consumer electronics, and household appliance molds worldwide — AISI P20 or AISI P20+Ni forging is the technically correct and economically optimal choice. The total cost of ownership (material cost + machining cost + heat treatment cost + mold service life) consistently favors P20 over alternatives for standard thermoplastic applications. We supply all grades listed above as forging parts — contact us to discuss which is best for your specific project.

Melting Methods for AISI P20 Forgings: Which Process Is Right for Your Application?

The melting and refining process used to produce the AISI P20 steel billet that is subsequently forged has a direct and significant impact on internal cleanliness, inclusion rating, fatigue resistance, and polishability of the final forged component. Jiangsu Liangyi offers all major commercial melting routes for AISI P20 series forgings, each with a different cost-performance profile. Every order regardless of melting route is supplied with a full Mill Test Certificate (EN 10204 3.1 or 3.2 as requested).

1. EAF (Electric Arc Furnace) — Cost-Effective Standard Grade

Electric Arc Furnace melting is the most widely used and cost-efficient steelmaking route for AISI P20 series forgings. EAF-grade P20 meets all standard chemical composition requirements and is fully suitable for the majority of injection mold and die casting tooling applications where section size is under 300 mm and internal cleanliness requirements are ASTM A388 standard ultrasonic class. This is the most cost-effective option for buyers with budget-sensitive projects or standard mold base and holder plate applications where maximum material performance is not the primary driver.

2. EAF+LF+VD (Ladle Furnace + Vacuum Degassing) — Improved Cleanliness & Consistency

The addition of a ladle furnace (LF) refining step and vacuum degassing (VD) to the EAF route provides the significantly improved internal cleanliness compared to standard EAF material.The LF step allows precise chemistry adjustment and homogenization, while the VD step reduces dissolved hydrogen content to below 1.5 ppm — critical for preventing hydrogen-induced cracking in thick AISI P20 forgings — and removes non-metallic oxide inclusions. EAF+LF+VD material is our standard recommendation for AISI P20 forgings from 300–600 mm effective section and all AISI P20+Ni forgings intended for large automotive molds.

3. EAF+ESR (Electro Slag Remelting) — Maximum Cleanliness for Demanding Applications

Electro Slag Remelting (ESR) is a secondary refining process where the primary EAF-melted electrode is re-melted by passing a high current through a molten slag bath. The slag acts as a liquid filter, absorbing oxide inclusions and sulfide stringers from the liquid steel as it resolidifies into a new ingot with dramatically improved internal cleanliness. ESR-grade AISI P20 and AISI P20+Ni delivers inclusion ratings that are typically 2–3 ASTM cleanliness grades better than EAF material, with finer carbide distribution and a more uniform microstructure throughout the cross-section. This translates directly to better mirror polishability (VDI 3–6 achievable on well-machined and polished surfaces), higher fatigue resistance for long-run mold tooling, and more predictable, uniform through-hardness in thick sections over 600 mm. ESR-grade material is our recommendation for premium automotive A-surface molds, optical lens molds, medical device molds, and zinc die casting tooling requiring over 800,000 shot life.

4. EAF+PESR (Protective Atmosphere ESR) — Premium Grade for Critical Applications

Protective atmosphere ESR (PESR) performs the ESR remelting step under an inert atmosphere (argon or nitrogen) rather than in open air. This prevents nitrogen pickup and further oxidation of reactive elements during remelting, producing a slightly cleaner and more chemically consistent product than standard ESR for the most extreme applications. PESR is usually specified for AISI P20+Ni forgings for precision optical or medical-grade dies where the absolute highest level of internal cleanliness and microstructural homogeneity is required.

5. VIM+PESR (Vacuum Induction Melting + Protective Atmosphere ESR) — Ultra-Premium Grade

The VIM+PESR route produces the cleanest, most chemically precise AISI P20 material available commercially. Vacuum induction melting (VIM) allows precise alloy additions under vacuum, eliminating atmospheric contamination during primary melting, followed by PESR for final inclusion removal and solidification control. This double-vacuum refined material is specified only for the most demanding aerospace tooling or ultra-precision optical mold applications where the standard ESR grade cannot meet the required inclusion or cleanliness specifications. VIM+PESR material carries a significant price premium over EAF routes and is typically only justified when the application requirements specifically demand it.

Chemical Composition of AISI P20, P20+Ni & P20+S Steel — Full Three-Grade Comparison

The following table shows the standard chemical composition ranges for all three AISI P20 series steel grades as manufactured in our Jiangyin, China facility. Full chemical composition test results are provided for every heat of steel on the EN 10204 3.1 or 3.2 Mill Test Certificate supplied with each order. Our in-house spectrometry laboratory verifies chemistry at billet stage before any forging work begins.

Note: Actual certified compositions are provided in the EN 10204 3.1/3.2 Mill Test Certificate for each specific heat and order. Slight variations within the above ranges may occur between different heats while remaining fully compliant with the applicable standard.

Heat Treatment of AISI P20 Series Forged Steel: Full Technical Process Guide

Heat treatment is the process step that converts the forged AISI P20 steel microstructure from its as-forged state into the pre-hardened, quenched and tempered condition that provides the Brinell ~300 HB hardness and excellent combination of strength, toughness, and machinability that AISI P20 is valued for. At Jiangsu Liangyi, heat treatment is performed in-house in our dedicated, computer-controlled heat treatment furnaces — not subcontracted — ensuring full traceability and tight process control for every forging we produce.

Step 1 — Forging Temperature Control

Proper forging temperature management is the first step in ensuring a high-quality AISI P20 heat treatment outcome. Forging at the correct temperature range makes sure the steel is fully austenitic and deformable without excessive grain growth, and it can produce the refined grain matrix that will respond most uniformly to subsequent heat treatment.

• Recommended forging start temperature: 2000°F (1093°C) — above this, grain growth accelerates rapidly and can compromise subsequent heat treatment response
• Minimum forging finish temperature: 1700°F (927°C) — forging below this temperature when the steel is no longer fully austenitic causes cracking and unacceptable microstructural defects
• All forgings are pyrometer-monitored at our facility; forging is stopped and the part is reheated if temperature drops below the minimum limit

Step 2 — Annealing (Stress Relief After Forging)

Immediately after forging, AISI P20 forgings are annealed to relieve residual forging stresses, soften the steel for any required rough machining, and homogenize the microstructure before the final quench and temper cycle. Skipping or rushing the annealing step is one of the most common causes of distortion and cracking during subsequent hardening of thick AISI P20 forgings.

• Annealing temperature: 1450–1500°F (788–816°C)
• Soak time: Minimum 1 hour per 25 mm of maximum section thickness, plus 2 hours minimum total hold
• Controlled cooling rate: Maximum 30°F (17°C) per hour down to 1000°F (538°C), then air cool — faster cooling risks hardening the surface, leaving dangerous residual stress that causes cracking during the subsequent hardening quench
• Resulting hardness after annealing: Maximum Brinell 207 HB — verified by our QC team before any machining is performed
• Important note: Normalizing (air cooling from austenitizing temperature) is not recommended for AISI P20 series steels. The Cr-Mo alloying system means even air cooling can produce martensite in the surface zone of thick sections, creating residual stresses that are incompatible with the controlled distortion requirements of precision mold steel production.

Step 3 — Hardening (Austenitizing and Quenching)

The hardening step transforms the annealed ferritic microstructure of AISI P20 into martensite — the hard, body-centered tetragonal phase that provides the high hardness of the pre-hardened condition. The key to successful hardening of AISI P20 forgings, particularly in large sections, is controlled consistent heating to avoid thermal shock cracking, and an appropriately fast quench to get through-hardening without excessive quench distortion.

• Heating rate: Slow, uniform — maximum 150°C/hour for sections over 200 mm to prevent thermal gradients that cause cracking
• Preheat: Optional preheat at 600–650°C for 1 hour per 25 mm section is recommended for sections over 400 mm to minimize thermal shock during heating to austenitizing temperature
• Austenitizing temperature: 1500–1600°F (816–871°C) — temperature is selected within this range based on section size; heavier sections use the higher end to ensure full austenitization at the core
• Soaking time at austenitizing temperature: 60 minutes per inch (25 mm) of maximum section thickness — this ensures full austenitization throughout even the core of the heaviest forgings
• Quench medium: Oil quench — oil quenching is used for AISI P20 because it provides the necessary cooling rate for through-hardening while producing lower thermal shock and quench distortion than water or polymer quenching. The relatively high Cr and Mo content of AISI P20 provides sufficient hardenability to through-harden even in oil.

Step 4 — Tempering (Final Hardness Adjustment)

The as-quenched martensite of the AISI P20 is hard but brittle – immediate tempering after quenching is required to restore the toughness and dimensional stability required for mold applications. Tempering is performed at a temperature selected to give the final hardness required by the customer. Higher tempering temperatures give lower hardness and higher toughness.For standard pre-hardened AISI P20 mold steel supply, the target is Brinell 280–320 HB (typically achieved at 580–620°C tempering temperature).

• Tempering temperature range: 300–1200°F (149–649°C)
• Tempering soak time: Minimum 2 hours per 25 mm section — undertempering in thick sections is a significant quality risk
• CRITICAL — Double temper: For sections over 300 mm, a double temper is performed. After the first temper and full cool to room temperature, the part is retempered at the same or slightly lower temperature. This ensures full stress relief and conversion of any retained martensite or bainite from the first temper cycle.
• Hardness verification: Brinell hardness is measured at minimum three positions on each forging after tempering — at the surface, quarter-section, and center (where accessible via coupon or bore) — and results are recorded on the MTC

Mechanical Properties of AISI P20 Series Forged Steel

The following tables provide typical mechanical property data for AISI P20 series forged steel in the quenched and tempered condition as supplied by Jiangsu Liangyi. Note that mechanical properties depend on section size, exact heat treatment parameters, and heat-to-heat variation within the compositional specification — values below are representative of EAF+LF+VD grade material at standard pre-hardened supply condition (approximately Brinell 300 HB). ESR-grade material typically delivers 10–20% higher impact toughness values at equivalent hardness.

Typical Tensile Properties (Standard Pre-Hardened Condition, Brinell ~300 HB)

Hardness vs Tempering Temperature (AISI P20+Ni, after hardening at 850°C / oil quench)

The following data shows how tempering temperature can be used to dial in a specific final hardness for custom heat treatment requirements. This curve is valid for sections up to approximately 100 mm; larger sections will show slightly lower core hardness at any given tempering temperature due to reduced quench rate at the center.

Note: The standard pre-hardened AISI P20 supply condition targets approximately Brinell 280–320 HB (≈ 29–33 HRC). Custom hardness from Brinell 230 HB to Brinell 380 HB is available upon request by specifying a custom tempering cycle. Contact our technical team with your hardness and toughness requirements.

AISI P20 Forging Parts: Applications, Industry Cases & Engineering Rationale

The following section documents the primary end-use applications for AISI P20 series forging parts supplied from our Jiangyin, China factory, with engineering context explaining why AISI P20 is specified for each application and what specific material characteristics are most critical. This application knowledge is drawn from over 25 years of direct experience supplying mold steel forgings to global customers in these industries.

1. Automotive Plastic Injection Mold Manufacturing

Automotive injection molds represent the largest single end-use market for AISI P20 forged steel worldwide. A typical full-size automotive door panel mold may weigh 15–80 tonnes, with cavity inserts and cores machined from blocks up to 800 mm thick — a section size where only forged AISI P20+Ni can guarantee uniform through-hardness and consistent mechanical properties from surface to center.

The specific performance characteristics that make AISI P20 the automotive mold industry standard are: the pre-hardened Brinell 300 HB condition eliminates heat treatment distortion risk after cavity machining; chromium content ensures the fine carbide distribution needed for uniform, defect-free cavity polishing to VDI 6–12 surfaces for visible interior trim parts; and the Cr-Mo hardenability allows the entire cross-section of a 600 mm block to achieve within ±30 HB of the target hardness in oil quench — ensuring consistent machining behavior from the first cut to final polishing. We supply AISI P20+Ni forged blocks up to 30,000 KGS per piece for the largest automotive body panel molds, and step-forged AISI P20 bars for ejector pins, lifters, and core assemblies in the same programs.

2. Large Household Appliance Mold Manufacturing

Injection molds for refrigerator door liners, washing machine drums, and large air conditioner housings require large, flat forged blocks with uniform hardness across wide, thin sections — a geometrically challenging shape that exposes any through-hardening weakness in the material. A mold block for a full-size washing machine drum may be 1,200 × 800 × 200 mm with a target hardness of Brinell 300 ± 20 HB across its entire width.

For such applications, our EAF+LF+VD or EAF+ESR AISI P20 forged plates are the standard specification, because the vacuum degassing step eliminates the hydrogen that would otherwise cause flaking in the core of large, slowly cooled sections. We perform a prescribed slow-cool protocol after forging on all plate dimensions over 1,000 mm width, and provide hardness maps (multiple surface and mid-section Brinell measurements) upon request to demonstrate uniform hardness distribution before shipment.

3. Zinc Alloy & Aluminum Die Casting Tooling

While AISI H13 is the standard for high-pressure aluminum die casting dies, AISI P20 and AISI P20+Ni are widely and successfully used for zinc (Zamak) die casting tooling and low-pressure or gravity aluminum casting dies, particularly where the lower injection pressures and temperatures of zinc casting do not demand the hot hardness and thermal fatigue resistance of fully hardened H13. The economic advantage is significant: a full set of zinc die casting inserts and cores in AISI P20+Ni can be produced in 60–70% of the material cost of H13, with acceptable die life of 300,000–800,000 shots in most zinc casting applications when ESR-grade material is specified.

Our AISI P20+Ni seamless rolled rings are commonly used as die sleeve rings and ejector sleeve housings in zinc die casting machines, where the ring-rolled circumferential grain orientation provides maximum resistance to hoop stress fatigue from the cyclic injection pressure loading. We recommend ESR melting route for all AISI P20 series die casting tooling to minimize subsurface inclusion population that can initiate fatigue cracks under thermal cycling.

4. Medical Device & Precision Consumer Electronics Molds

AISI P20+Ni produced by ESR or PESR melting is the preferred material for precision injection molds for medical device housings, syringe barrels, IV connector bodies, and similarly demanding applications where dimensional tolerances of ±0.02 mm or better are required over million-shot production runs. The enhanced nickel content of AISI P20+Ni provides the combination of improved impact toughness (resisting corner chipping in thin-walled cavity features) and better through-hardness uniformity in medium to large mold sections (300–600 mm) that standard AISI P20 cannot match.

For consumer electronics molds — smartphone housing molds, laptop lid molds, and tablet frame molds — the polishability of AISI P20+Ni ESR to VDI 3–6 surface finish is a key selection criterion, as these molds require mirror or near-mirror cavity surfaces to produce the Class A cosmetic parts demanded by electronics OEMs. ESR-grade AISI P20+Ni consistently achieves this surface finish level, while standard EAF material is less predictable due to higher inclusion content that creates microscopic pitting during fine polishing operations.

5. Mold Bases, Holder Plates & Standard Mold Components

Beyond cavity inserts and cores, a significant portion of every injection mold consists of structural components — A and B plates, support pillars, ejector plates, guide pin bushings, and slide carriers — that require good machinability and dimensional stability but not the premium material quality of the cavity inserts themselves. For these structural mold components, standard AISI P20 (EAF or EAF+LF) is the cost-optimized choice. We supply AISI P20 forged flat bars and blocks specifically for mold base manufacturing in the full range of standard international mold base plate sizes, as well as custom dimensions to your drawing.

How to Specify and Order Custom AISI P20 Forgings: A Practical Buyer's Guide

After 25+ years supplying AISI P20 forgings to buyers across 50+ countries, we have found that the most common source of delays and cost overruns in AISI P20 forging orders is incomplete or ambiguous technical specifications provided at the time of inquiry. This section provides practical guidance on what information to include in your AISI P20 forging inquiry to receive the fastest and most accurate quotation from our factory.

Minimum Information Required for a Formal Quotation

In order to provide the customer with a formal quotation for Price and Lead time for AISI P20 forging parts, the following technical information is required:

• Steel grade: Specify AISI P20 or AISI P20+Ni or AISI P20+S. If you are unsure, tell us about your application and we will suggest the best grade.
• Forging shape and dimensions: Provide a dimensioned drawing in PDF, DWG, or DXF format, or specify the shape type (round bar, flat bar, ring, block, hollow bar) with all relevant dimensions (OD/ID/height for rings; diameter and length for bars; L×W×H for blocks). Include allowances for machining stock if you require as-forged tolerances (specify standard — DIN 7527 Part 6 or ASTM A788 or your own tolerance drawing).
• Weight or quantity: Specify required quantity in pieces, approximate weight per piece. If dimensions are provided we can calculate weight from dimensions for rings and blocks.
• Supply condition: Specify whether you require as-forged, annealed (soft), or pre-hardened and tempered (Q+T) condition. If Q+T, specify the target hardness range (e.g., Brinell 280–320 HB or a specific HRC range).
• Melting route: EAF, EAF+LF+VD, EAF+ESR, EAF+PESR or VIM+PESR. If you don’t specify one, we’ll recommend one based on your application and section size.
• Testing and certification requirements: Specify the required MTC type (EN 10204 3.1 or 3.2), ultrasonic inspection class (ASTM A388, SEP 1921, or EN 10228-3/4), surface inspection (magnetic particle or dye penetrant), and any additional tests (impact testing at specific temperature, hardness maps, etc.).
• Delivery destination and required shipping terms (Incoterms): FOB Shanghai/Tianjin, CIF named port, DDP, or other terms.

Common Mistakes Buyers Make When Sourcing AISI P20 Forgings

Based on our experience of reviewing purchase orders and buyer inquiries, we summarize the following most frequent specification errors that result in wrong material being shipped, delays, or unexpected costs:

• Specifying "P20" without specifying "forged" or "rolled": Many Chinese and Indian steel suppliers will quote and supply hot-rolled or continuous cast AISI P20 plate against an inquiry that does not explicitly specify "open die forged." Forged and rolled P20 have the same chemistry but significantly different internal quality and mechanical properties. Always specify "open die forged" and request forging reduction ratio documentation.
• Omitting the ultrasonic inspection class: AISI P20 forgings can be produced to a range of internal quality levels, from unscanned to SEP 1921 Class C/c or ASTM A388 Class D. Without specifying a requirement, many suppliers will not perform any ultrasonic inspection. Insist on a minimum inspection class appropriate for your application — for cavity inserts, we recommend SEP 1921 C/c or equivalent as a minimum.
• Specifying only hardness without specifying tempering temperature range: Different AISI P20 producers may achieve the same Brinell 300 HB surface hardness using very different tempering temperatures, resulting in different levels of toughness and residual stress. Always specify both the hardness range AND minimum impact toughness (e.g., Charpy KV ≥ 30 J at room temperature) for critical mold applications.
• Ordering standard P20 for sections over 300 mm: As described in the grade comparison above, standard AISI P20 (without Ni addition) cannot reliably achieve uniform through-hardness in sections over 300 mm effective diameter or thickness. For large sections, always specify AISI P20+Ni.
• Not specifying surface condition and dimensional tolerance: "As-forged" dimensions can vary significantly between suppliers. If you need machining stock consistently within ±5 mm, specify this explicitly. If you need rough-machined surfaces (Ra 12.5 µm or better), specify rough machining service in the order. Assuming a standard tolerance without checking can result in forgings that require excessive material removal before your machining begins.

Our Custom Service & Global Support for AISI P20 Forging Customers

Jiangsu Liangyi operates as a fully integrated, single-source AISI P20 forging manufacturer — from steel procurement through to finished, inspected, and certified forging parts ready for your machining. This is fundamentally different from the model of many Chinese steel trading companies or distributors who source forgings from multiple sub-suppliers and apply their own quality inspection on top. Our single-source model means:

• Custom Forging Service:  We can produce custom parts based on your drawings, samples, or technical requirements — from  single pieces to long-term serial production contracts. We maintain customer-specific tooling in our facility for repeat orders, eliminating tooling lead time on subsequent orders.
• Complete Testing & Certification: Full EN 10204 3.1 or 3.2 Mill Test Certificate for every order — not a generic material certificate, but a piece-specific document traceable to the heat number of steel, the forging lot, and the heat treatment batch. Included data: chemical composition (full 8-element analysis), mechanical properties (tensile, elongation, reduction of area, Charpy impact), hardness (surface and where applicable cross-section), and NDT results (UT class, MT/PT surface inspection).
• Flexible Heat Treatment: As-forged, annealed/softened, or fully quenched and tempered to any hardness from Brinell 220 to 380 HB. Double temper protocol available for all sections over 300 mm. Induction surface hardening or case hardening available for specific requirements — contact us to discuss.
• Precision Machining: Optional rough machining (remove forging scale and draft angles, machine to dimensional drawing with 2–5 mm machining allowance remaining), semi-finish machining (±0.5 mm tolerance), or finish machining (±0.1–0.2 mm tolerance) service — reducing your post-receipt machining cost and enabling direct use of our forgings in your mold shop. Boring, turning, milling, drilling, grinding, and CNC contouring all available.
• Surface Treatment: Nitrocarburizing, black oxide coating, rust-preventive oil coating, and bare clean surface options for shipping. Long-term storage rust prevention (VCI packaging + silica gel + sealed crating) available for stock or strategic inventory orders.
• Worldwide Shipping & Logistics: Supply sea freight (FCL or LCL consolidation from Shanghai), air freight for urgent small forgings and express courier for samples. Door-to-door service and customs clearance support are available for most destinations worldwide.We have supplied AISI P20 forgings to customers located in USA, Germany, Japan, South Korea, Australia, Turkey, Mexico, Brazil, India and 40+ other countries.
• Expedited Production: Standard lead time is 15–25 days from order confirmation for most AISI P20 series forgings. For urgent orders, our expedited production schedule — with dedicated furnace capacity reservation and priority scheduling — can deliver most forgings in 10–15 days. Expedited air freight delivery within 3–5 days of dispatch. Please contact us with your required delivery date when inquiring.

Quality Control & Inspection for AISI P20 Forged Parts: Our Full QC Process

Quality at Jiangsu Liangyi is not a final inspection activity; it is built into every step of the production process from raw material receipt to shipment approval. We are an ISO 9001:2015 certified manufacturer and our quality management system controls every process step. Our QC team has the right and responsibility to stop production at any stage if a deviation from specification is found. Following is our full quality control process for AISI P20 forging:

Stage 1: Incoming Raw Material Inspection

Every heat of AISI P20 series steel billet received at our facility is quarantined and verified before being released to production. Incoming inspection includes: full 8-element chemical composition verification by our in-house optical emission spectrometer (OES), comparison of our measured composition against the supplier's mill certificate, and visual/dimensional inspection of billet condition. Any heat where our measured composition falls outside the AISI P20 grade specification is rejected and returned to the steel mill — no exceptions.

Stage 2: Forging Process Control

During forging, process control measures include: real-time pyrometric temperature monitoring of the forging billet and workpiece, documented forge reduction ratio (minimum 3:1 for bars and blocks; minimum 5:1 for critical large components), and dimensional verification of forging shape against the work order drawing before the part is transferred to heat treatment. Forging process records are retained for full traceability.

Stage 3: Heat Treatment Monitoring & Documentation

Our heat treatment furnaces are fitted with calibrated thermocouples and automatic temperature recorders, keeping full time‑temperature records for every production batch. We calibrate the furnaces every quarter using traceable reference instruments. The furnace temperature chart is a mandatory part of the traceability record for every AISI P20 forging order and is available to customers on request. Post-heat-treatment hardness is measured and recorded before any forging is released to final inspection.

Stage 4: Non-Destructive Testing (NDT)

NDT is the most critical inspection step for forged mold steel, since it identifies internal discontinuities invisible to surface inspection that can lead to catastrophic mold failure in service:

• Automatic ultrasonic testing (UT): Two dedicated ultrasonic testing gantries with automatic drive and digital data acquisition systems for full volumetric scanning of round bars, flat bars, and disc-shaped forgings. Scanning is performed at standard forging frequency (2.25 or 4 MHz) with sensitivity set to the specified reference reflector size (e.g., ∅ 2 mm FBH for SEP 1921 Class C/c).
• Manual ultrasonic testing: For irregular-shaped forgings, rings, hollow bars, and complex profiles that cannot be scanned automatically, our experienced UT operators perform manual contact UT scanning based on ASTM A388, EN 10228-3, EN 10228-4, or SEP 1921 as specified.
• Magnetic particle testing (MT): All AISI P20 forgings with specified surface integrity are 100% wet fluorescent magnetic particle tested (WFMT) to ASTM E1444 or EN 10228-1 for linear indications on surface and near surface such as forging laps, seams, and quench cracks. Acceptance Criteria: No linear indications accepted irrespective of length.
• Dye penetrant inspection (PT): For austenitic materials or where MT is not applicable, liquid penetrant inspection per ASTM E165 or EN 10228-2 is available as an alternative surface inspection method.

Stage 5: Dimensional and Microstructural Inspection

• Dimensional inspection: All finished forgings are measured against the customer drawing using calibrated measuring instruments including micrometers, vernier calipers, bore gauges, and coordinate measuring machine (CMM) for complex or precision-machined forgings
• Optical microscope: Metallographic coupon samples (when specified) are examined at 100×–500× magnification to verify grain size (ASTM E112), inclusion rating (ASTM E45 or DIN 50602), and absence of decarburization, banding, or abnormal microstructural features
• Scanning electron microscope (SEM): Available for detailed microstructure analysis, inclusion characterization, and failure investigation on special request

Stage 6: Chemical and Mechanical Property Testing

• Chemical composition: Full 8-element OES analysis (C, Si, Mn, P, S, Cr, Mo, Ni) performed for every heat of AISI P20 steel before forging and again from a coupon cut from a representative forging in each heat treatment batch
• Tensile testing: Longitudinal tensile specimens machined from coupons cut from the body of selected forgings — tested for proof strength (Rp0.2), tensile strength (Rm), elongation (A5), and reduction of area (Z) per ISO 6892-1 or ASTM E8
• Impact testing: Charpy V-notch impact test at room temperature (+20°C) or at other specified temperatures per ISO 148-1 or ASTM E23
• Hardness testing: Brinell hardness (HBW 10/3000) measured at minimum three positions on each forging — typically two surface positions and one mid-section position via coupon or bore. All hardness test equipment is calibrated to traceable reference blocks.

Stage 7: Final Documentation and Release

Before any AISI P20 forging order is released for packing and shipment, the complete documentation package is signed off by our Quality Manager and comprises: production work order with full traceability records, EN 10204 3.1 or 3.2 Mill Test Certificate showing all test results, NDT inspection reports with scanning records and hardness chart records, dimension test records and, where applicable, furnace temperature charts from heat treatment. This complete documentation package is transmitted to the customer before or together with the shipment, making sure that your incoming inspection and material certification requirements are fully met upon receipt.

Frequently Asked Questions About AISI P20 Forgings