Jiangsu Liangyi manufactures custom forged steel crankshafts and forged shafts for heavy-duty industrial uses including frac pumps, marine diesel engines, compressors, mining equipment, presses and general machinery. We keep the main production chain in-house to improve process control, traceability and documents consistency.
This page keeps the technical depth of the original article while presenting the information in a clearer format for engineers, sourcing teams and buyers evaluating custom forged crankshaft suppliers.
This page answers the major commercial and technical questions buyers usually ask before sending an RFQ: what forged steel crankshafts are used for, why forged is often preferred over cast in heavy-duty service, which material grades are available, what the manufacturing process looks like, what certificates can be supplied and what information is needed to receive an accurate quotation.
Established in 1997, Jiangsu Liangyi Co., Limited is an ISO 9001:2015 certified China manufacturer of custom forged steel crankshafts and forged shafts for demanding industrial uses. Our factory covers about 80,000 square meters and integrates steel melting, open die forging, heat treatment, rough machining, finish machining and inspection within one manufacturing system.
This comprehensive approach is important to industrial buyers because forged crankshaft performance is not determined by shape alone. It depends on steel quality, forging ratio, grain flow control, heat treatment stability, machining precision and inspection standards. When these steps are managed under one system, traceability and consistency are easier to maintain across both sample and mass production.
We can make single-piece weight ranges from 30 kg to 30,000 kg and has an annual capacity of 120,000 tons. Our forged crankshafts and forged shafts are supplied to industries such as oil & gas, marine, mining, engineering machinery, metal forming, compressors and power generation. Production can be arranged according to customer 2D and 3D drawings, material specifications and inspection requirements.
Custom forged steel crankshafts, forged eccentric shafts and other heavy-duty rotating forged parts for main industries.
In-house melting, open die forging, heat treatment, CNC machining and NDT inspection under one quality system.
Better quality traceability, fewer process gaps, stronger technical documents control and improved consistency for export projects.
For heavy-duty rotating and reciprocating equipment, forged steel crankshafts are mainly used where reliability under cyclic load is more important than the lower upfront cost that cast alternatives may sometimes offer. The reason is straightforward: the internal structure of a forged part can usually be controlled more effectively than that of a cast part, especially when the use involves repeated stress reversals, torsional loading, shock and continuous operation.
Open die forging helps refine and direct the metal flow more effectively than casting. It matters a lot for a crankshaft because life is heavily influenced by internal continuity and structural reliability. Better grain flow can improve the resistance against crack initiation under repeated loading.
Compared with cast parts, forged crankshafts generally reduce the risk associated with porosity, shrinkage cavities and other casting-related discontinuities. This improves confidence in the part for high-value and safety-critical machinery.
Forged crankshafts are often chosen for high torque, high pressure and impact-related service because their mechanical properties can be more uniform and more suitable for severe industrial duty cycles.
Although the initial manufacturing route is more demanding, forged crankshafts can reduce shutdown frequency, maintenance interventions and replacement cost in the long run when the use is heavy-duty.
In short, forged steel crankshafts are not simply a good alternative; in many oilfield, marine, mining and press uses, they are the more technically appropriate solution because structural reliability and fatigue performance are central to machine uptime.
Our custom forged steel crankshafts and forged shafts are manufactured for uses where fatigue strength, torsional rigidity, wear resistance, impact toughness and traceable documents are important. The following industries represent the most common uses for this product category.
Oilfield pumping systems create high cyclic loading, severe torque fluctuation and demanding reliability requirements. Forged crankshafts used in frac pumps, high pressure plunger pumps, triplex pumps and quintuplet pumps must therefore combine sound internal structure, suitable alloy selection, correct heat treatment and complete inspection records. For these uses, buyers often request API-related documents and third-party inspection support in addition to mechanical performance.
Our forged crankshafts for oil and gas duty can be supplied for shale gas, traditional field service and pressure-related pumping systems. Depending on project specification, support can be consistent with API 6A, NACE MR0175 and EN10204 certificate requirements.
Marine crankshafts work under long continuous service, torsional vibration and strict maintenance planning. We produce forged crankshafts for heavy-duty Marine diesel engines, propulsion components and auxiliary power systems. Buyers place a high value on structural strength, grade-related documents, and long-term size stability.
Mining services often put parts in situations where they have to deal with grinding media, impact loads, and hard-to-reach places for maintenance. Forged crankshafts and shafts used in heavy machinery, mud pumps, sludge pumps, and mineral processing systems must be strong, tough, and able to last in hard conditions.
High-speed cyclic machinery requires stable geometric shapes and predictable fatigue behavior. In presses and cold heading systems, the crankshaft is a main load-bearing motion part. We support forged crankshafts for forming systems where manufacturers need repeatable size accuracy, reliable grain flow and controlled machining quality.
Buyers in different regions often use different standards, material naming conventions, certificate expectations and logistics priorities. This section highlights the main concerns raised by customers in major export markets.
Common interests include ASTM and AISI grade matching, API-related documents for oilfield pumps, urgent maintenance schedules, compressor service and third-party inspection coordination.
European buyers mostly look for EN and DIN references, EN10204 3.1 or 3.2 certificates, Marine witness requirements, full traceability, and size accuracy.
Demands mainly focus on oilfield reliability, high-temperature services, material selection related to corrosion, reliable documentation and schedule support for large industrial projects, etc.
This region frequently requires flexibility for prototypes and repeated batches, mixed standard systems and support for automotive, industrial equipment and machinery manufacturing chains.
Mining, slurry handling, mineral processing and marine service are the dominant drivers, with strong interest in wear-resistant materials, impact toughness and shutdown-sensitive delivery timing.
Industrial buyers often compare crankshaft suppliers not only by price, but by how clearly they explain and control the manufacturing route. The process below preserves and strengthens the technical depth of the original article.
A clear process explanation helps buyers evaluate manufacturing control, traceability and quality risk management before placing an order. It also makes technical review easier when different suppliers are being compared.
This part gives procurement teams a quick overview of their capabilities in terms of size range, process route, machining scope, inspection support, and export-related document.
| Capability Item | Available Range or Support | Commercial Relevance |
|---|---|---|
| Single-piece weight | 30 kg to 30,000 kg | Supports both sample parts and large heavy-duty industrial crankshafts |
| Maximum length | 15 meters | Suitable for large marine and heavy equipment projects |
| Annual capacity | 120,000 tons | Supports repeat supply and larger long-term programs |
| Manufacturing route | Melting, forging, heat treatment, machining, inspection | Improves traceability and process coordination |
| Inspection scope | Chemistry, mechanical tests, UT, MT, PT, dimensions | Matches industrial documentation expectations |
| Certificate support | EN10204 3.1 / 3.2 and third-party coordination | Useful for export projects and critical service approvals |
Forging improves internal continuity and allows a more application-oriented grain flow path compared with cast alternatives.
Controlling forging and heat treatment helps to enhance the consistency of strength, toughness and fatigue-related properties.
Production can be custom as per drawing, material grade, heat treatment target, machining stage and inspection scope.
Managing all steps in-house makes the documentation consistent and reduces coordination gaps between subcontractors.
We can offer different material and process for different uses such as oilfield, marine, mining or metal forming.
We can provide EN10204 certificates and accept a third-party witness, thus helps us move more smoothly across international markets.
Material choice is one of the most important decisions in a forged crankshaft project. Buyers often review the product category together with the steel grade because service load, toughness, hardenability, corrosion resistance and cost all influence the final choice.
| Material Category | Main Grades | Main Use Direction | Main Benefit |
|---|---|---|---|
| Medium Carbon Alloy Steel | SAE 4140, 42CrMo4, 1.7225, SAE 4130, SCM440 | General industrial pumps, presses and rotating equipment | Balanced strength, toughness and machinability |
| High Strength Alloy Steel | 4340, 34CrNiMo6, 4330V, 4330V Mod, 30CrNiMo8 | Heavy-duty frac pumps, marine engines and mining service | Higher strength and stronger fatigue potential |
| Case Hardening Steel | 8620, 16MnCr5, 17CrNiMo6, SCM420 | Uses requiring hard surface and tough core | Wear resistance with retained core toughness |
| Martensitic Stainless Steel | 410, 420, A182-F6a, A182-F6b | Pump and valve related service | Strength with moderate corrosion resistance |
| Austenitic and Duplex Stainless Steel | 304, 316, 316L, F51, F53, 904L, 254SMO | Marine, petrochemical and corrosive environments | Improved corrosion resistance |
| Nickel-Based Alloy | Inconel, Monel, Hastelloy series | Extreme temperature or severe corrosion environments | Special-service durability |
What is the best material for a forged steel crankshaft? The answer depends on the use. SAE 4140 and 42CrMo4 are common because they offer a strong balance of cost and performance. For more severe duty, 34CrNiMo6 and 4340 are frequently considered. For corrosive service, stainless steel or nickel-based alloys may be more suitable.
We can review load condition, shock risk, pressure level, corrosion environment, sizes, heat treatment target and standard preference to help identify a more appropriate material route for your project.
In forged crankshaft procurement, documentation is not a side topic; it is part of the product. EPC contractors and repair companies require evidence covering chemistry, heat treatment, mechanical properties, NDT status and size acceptance. Our quality system is built to support those expectations.
This section helps buyers prepare a clearer RFQ without reducing the technical depth of the page. A more complete inquiry package usually leads to faster review and a more accurate quotation.
A clear RFQ improves quotation accuracy, shortens technical review time and reduces the risk of mismatch between buyer expectation and delivered scope.
Forged steel crankshafts are used in heavy-duty equipment such as frac pumps, marine diesel engines, compressors, mud pumps, mechanical presses, mining equipment and other systems where fatigue resistance, torsional strength and service reliability are critical.
Forged crankshafts usually offer better grain flow, lower internal defect risk, more reliable fatigue behavior and stronger structural consistency than cast crankshafts, which is why they are commonly chosen for high-load and high-cycle service.
Yes. We can produce the forged crankshafts according to customers' drawings.
According to the geometric shape and project requirements, we can manufacture single-forged crankshaft parts weighing up to 30 tons and with a length of up to 15 meters.
Depending on the project, documentation can include material certificates, heat treatment records, size reports, NDT reports and EN10204 3.1 or 3.2 certificates, with third-party witness coordination when required.
Lead time differs based on material grade, size, machining scope and inspection requirement. Sample orders may take 20 to 30 working days while larger production may take 30 to 45 working days. Specific delivery date depends on the order.
The manufacturer issues EN10204 3.1 with inspection data, and EN10204 3.2 has a third-party witness or inspection. The level of certificate needed depends on the project's requirements and the level of risk involved.
Please send the drawing, uses, material grade or use condition, sizes or part weight, quantity, machining scope, inspection requirement and delivery destination. This helps shorten the review time and improve the accuracy of the quotation.
If you need a custom forged steel crankshaft or forged eccentric shaft, send us your drawing, quantity, material requirement, use information and certificate requirement. We can review the technical package and provide a quotation solution with manufacturing and inspection scope as per your project.
Inquiry Email: [email protected]
Phone / WhatsApp: +86-13585067993
Website: https://www.jnmtforgedparts.com/
Factory Address: Chengchang Industry Park, Jiangyin City, Jiangsu Province, China
Working Hours: Monday to Friday, 8:00 AM – 6:00 PM (UTC+8)
Quotation Response Target: Initial reply within 24 working hours for complete RFQ packages