Low-carbon SWRCH6–16A series cold-rolled and hot-rolled wire rods are non-heat-treated steels designed for cold heading and cold extrusion applications. These materials are primarily used in the production of fasteners with lower strength requirements. Due to the high degree of cold heading deformation and complex shapes involved, these products demand excellent pickling and phosphating quality. When the cold heading deformation exceeds 1/3 of the original size, annealing is recommended for certain steel grades. It's advisable for customers to choose low-carbon grades like SWRCH6A, especially when manufacturing fasteners with significant cold heading deformation. Additionally, selecting wire material specifications that closely match the required dimensions can reduce drawing deformation and minimize work hardening effects.
Free return cold rolled steel and hot rolled wire rods have seen significant development in recent years. In 2004, Maanshan Iron & Steel Co., Ltd. initiated the National 863 Program "Research on High Performance and Low Cost Cold Rolled Steel" (2003AA331030), aiming to develop advanced, cost-effective technologies for producing cold heading steel wire with independent intellectual property rights.
For high-strength fasteners rated 8.8 and above, medium carbon or alloy steels are typically used. The production process usually involves hot rolling, spheroidizing annealing, cold drawing, cold forming, rolling, quenching, and tempering. Spheroidizing annealing is crucial to ensure sufficient plasticity for cold heading. During cold heading, materials may undergo up to 70–80% total deformation, requiring raw materials with controlled hardness (HRB82 or lower). Currently, spheroidizing annealing is one of the most time-consuming and energy-intensive steps in fastener manufacturing. However, new developments aim to simplify or even eliminate this step.
Maanshan Iron & Steel has developed unique hot-rolling technology for high-line production, resulting in specialized wire rods such as SWRCH35K-M, CH35A-M, SWRCH35K-MT, and CH35A-MT, suitable for fasteners exported to the U.S. market. These wire rods are ideal for hexagonal bolts and similar fasteners. For large deformation applications, spheroidizing annealing is still necessary, while for nuts, MFM-1 and MFM-3 wire rods have been successfully developed. MFM-2 eliminates both annealing and quenching + tempering, directly producing grade 8 nuts.
Non-tempered cold heading steel is widely used for high-strength bolts (8.8, 9.8, 10.9). Using this type of steel reduces the need for pre-drawing annealing and post-bolting quenching/tempering, streamlining the production process, saving energy, and reducing defects like oxidation and decarburization. Japan has already adopted industrial-scale production of such materials.
In 2005, Maanshan Iron & Steel participated in the National 863 Program "Research and Development of Non-tempered Steel Wire for Fasteners via Low Temperature Controlled Rolling and Cooling." In 2008, the company also undertook the National Support Program Project "Development of Low-Cost, High-Strength Non-Quenched and Tempered Cold-Rolled Steel Products for Steel Structure Joints."
The non-tempered steel series from Maanshan Iron & Steel uses micro-alloying, controlled rolling, and cooling techniques to achieve ultra-fine grain structures. These wire rods eliminate the need for raw material annealing and final heat treatment during fastener production, meeting current mechanical performance standards (GB/T3098.22-2009). This green manufacturing approach reduces energy use, costs, and environmental impact, while minimizing defects caused by traditional heat treatments.
Alloy cold heading steels such as 10B21, ML40Cr, and SCM435 are used for high-grade fasteners (8.8–12.9). Through strict process control, these materials deliver superior performance and cost-effectiveness, making them ideal for demanding applications.
Sanitary Pressure Relief Valves
A Sanitary Pressure Relief Valves is a type of self-acting device, designed for keeping tanks work properly. It can release air out of the tanks to maintain pressue, and also absorb air into tanks to be anti-vacuum. Sanitary Pressure Relief Valves including stainless steel sanitary pressure relief valves, food grade pressure relief valves, hygienic pressure relief valves, vacuum relief valves, air release valves. Kaysen Steel is a china manufaturer and supplier of stainless steel sanitary pressure relief valves, food grade pressure relief valves, hygienic pressure relief valves, vacuum relief valves, air release valves, we supply supperial quality stainless steel sanitary pressure relief valves,vacuum relief valves, air release valves in SS304, SS316, SS316L materials, size from 1/2"-4", DN15-DN100, connection types contains weld, clamp, thread types,etc
Sanitary Pressure Relief Valves Specification:
Material: SS304, SS316 or SS316L
Connection Standard: 3A, DIN, SMS, ISO, IDF
Port size: DN20-DN50, 3/4"-2"
Connection type: weld, clamp, thread
Gasket material: EPDM, FPM.
Pressure: 0.5-2bar, Vacuum:0.3-0.9bar
Temperature range: -10℃ to 120℃(EPDM)
Sanitary Pressure Relief Valves,Food Grade Pressure Relief Valves,Hygienic Pressure Relief Valves
Kaysen Steel Industry Co., Ltd. , https://www.chinasanitaryvalve.com