Production Of 440A Cold Rolled Stainless Steel Sheet And 304 321 316L 316Ti 440

Standard: ASTM A240, AISI industrial specification

Grades: 440A, common 440 series; 304,321,316L,316Ti

Outside Diameter (OD): Seamless 3.18–830mm, Welded 10.3–457mm

Wall Thickness: 0.2–60mm per ASTM tolerance

Length: 1m/6m/12m, max customized 12m

Schedule: Sch10/Sch40/Sch80 + custom schedule

Applications: Precision cutting tools, bearing parts, chemical equipment, high temp fittings, valve components

Key attributes

Products Description

This product line centers on high-hardness martensitic 440A/440 series stainless steel, matched with four classic austenitic grades (304,321,316L,316Ti), forming a dual system of high-wear martensite + anti-corrosion heat-resistant austenite, completely different from previous decorative-type 400-series or single heat-resistance stainless steel. Our factory integrates independent smelting calibration, precision cold rolling, finished sheet finishing and customized cutting, focusing on precision machinery, chemical and high-load industrial raw material supply, covering scenarios from conventional anti-rust structure to ultra-high hardness wear-resistant precision parts. All cold rolled sheets go through multi-pass fine rolling + sealed protective gas annealing to stabilize internal grain; available standard 2B base surface, customized BA/No.4 finish upon client request, stable dimensional consistency for follow-up machining, heat treatment and precision forming.

440A is high-carbon high-chromium martensitic stainless steel, the highest hardness grade among conventional commercial stainless steel, far superior to 420J2 in carbon content, chromium proportion and quenching hardness limit. Under annealed delivery state, the sheet can complete blanking, cutting and simple bending; after quenching & tempering heat treatment, hardness reaches HRC58~62, excellent anti-abrasion, compression resistance and edge holding performance. It owns better atmospheric rust resistance than ordinary martensitic steel, resisting dry air, light water splash corrosion, yet unsuitable for long-term immersion in salt water and strong acid environment. Conventional 440 base material is used as cost-effective substitute for 440A for medium-load wear parts, balancing production cost and service life. This grade is the core difference of this listing, focusing on tool and precision wear-resistant spare parts which other previously introduced stainless cannot replace.

Classic general-purpose anti-rust material with balanced comprehensive performance, non-magnetic after cold working, outstanding atmospheric anti-corrosion, widely used for conventional equipment shell, general structural parts, common pipeline outer lining. Good bending, welding performance without post-weld heat treatment, cost performance outstanding for conventional non-special harsh working conditions.

Titanium fixed carbon design eliminates welding intergranular corrosion risk, stable long-term service at 450~800℃ alternating high-temperature environment, specially for high-temperature pipeline cladding, heat exchange equipment structural plates, solving welding aging cracking defect of ordinary 304 under long-term high temperature.

Both add molybdenum element to boost chloride & dilute acid corrosion resistance. 316L ultra-low carbon avoids sensitization corrosion after large-area welding, ideal for chemical dilute acid equipment, coastal high-salt workshop equipment; 316Ti uses titanium stabilization technology, upgrades high-temperature creep resistance based on 316’s anti-corrosion advantage, applicable for high-temperature chemical reaction equipment accessories where 316L fails under continuous thermal load. The two austenitic grades form low-temperature anti-corrosion + high-temperature anti-corrosion matched solution for chemical industry.

Since finished products mainly supply precision machining factories and chemical manufacturers, our cold rolling production strictly controls internal inclusion and surface flaw. For high-hardness 440A sheets, we adopt special homogenization annealing craft to reduce internal stress, lower cracking probability during post-processing quenching; for molybdenum-containing 316L/316Ti and stabilized 321, controlled slow cooling annealing ensures uniform corrosion resistance across whole plate.

We support factory pre-processing service including fixed-size cutting, fine blanking according to client drawings, directly supplying semi-finished blanks and reducing customers’ secondary machining loss. All finished sheets attach anti-scratch PVC film to protect 2B surface during transport and processing.

1. 440A / 440 Focus Field: Precision Wear-Resistant Components: Industrial cutting tool blanks, bearing balls & bearing bush raw materials, measuring tool parts, food processing high-hardness cutter, pump valve core wear inserts; core advantage is high hardness to extend component service cycle under long-term friction.
2. 304 Conventional Industrial General Parts: General equipment casing, machine tool outer protection panel, indoor non-corrosive structural frame, conventional water treatment equipment shell.
3. 321 High-Temp Auxiliary Components: Boiler peripheral auxiliary plates, hot air pipeline wrapping sheet, high-temperature drying equipment inner lining.
4. 316L Chemical Low-Temp Anti-Corrosion Parts: Dilute acid storage tank lining, coastal factory equipment outer plate, electroplating workshop auxiliary structural sheet.
5. 316Ti High-Temp Chemical Equipment: High-temperature reaction kettle accessory plate, thermal chemical pipeline outer cladding, high-temperature waste gas treatment equipment lining.

Every batch undergoes chemical composition inspection, hardness test and surface defect detection before leaving factory; complete MTC material certification for global export customs clearance and factory incoming inspection. Flexible order mode: small sample order for customer heat treatment & performance testing, bulk large batch production for factory mass processing demand. Products are packed with waterproof kraft paper + plastic wrapping, thickened foam separation for thin high-precision sheets to avoid collision deformation during long-distance sea and land transportation.