420J2 Cold Rolled Stainless Steel Sheet 400 Series ASTM 2B AISI Bending Cutting

Standard: ASTM A240,AISI standard specification

Grades: 420J2 martensitic stainless steel (400 series)

Outside Diameter (OD): Seamless:3.18~830mm；Welded:10.3~457mm

Wall Thickness:0.2~60mm with ASTM tolerance control

Length:1m/6m/12m, customizable up to 12m

Schedule: Sch10/Sch40/Sch80 & non-standard custom schedule

Applications: Tool blank, mechanical spare parts, hardware fittings, food machinery parts, mould base

Key attributes

Products Description

Distinct from previous ferritic decorative grades (430/409/444) and stabilized heat-resistant steel (321/347), 420J2 belongs to high-carbon martensitic stainless steel of 400 series, core positioning on hardening & wear-resistant industrial machining raw material, highlighting customizable bending and cutting one-stop processing service, the mainstream quenching-hardenable stainless raw material for precision machinery manufacturing industry. All products adopt precision multi-pass cold rolling process and closed stress relief annealing, finished base surface is uniform standard 2B finish with compact grain structure, free from roller marks, pits and oxide impurities, laying stable foundation for subsequent heat treatment and mechanical forming.

420J2 features medium carbon chromium-only formula without nickel, its most prominent trait is adjustable hardness via quenching and tempering heat treatment. Under annealed delivery state, the sheet owns proper ductility to support cutting, bending, stamping and CNC forming; after finished part heat treatment, surface hardness can reach HRC48~58, outstanding abrasion resistance and compressive performance far surpass soft ferritic stainless and non-hardenable 300-series austenitic steel. It gains moderate atmospheric rust-proof capability against dry air and light mist erosion, applicable for dry indoor industrial operating environment; limited acid & salt resistance decides it is not suitable for coastal high-salt fog or strong acid soaking working condition, which forms clear application boundary with molybdenum-containing anti-corrosion grades like 316/444.

Different from 410 low-carbon martensitic steel with lower hardness ceiling, higher carbon content of 420J2 greatly improves final quenched hardness and wear resistance, specially developed for parts requiring long-term friction and anti-scratch performance, filling the blank of medium-hardness stainless blank material in mid-end machinery manufacturing.

Our supporting in-house deep processing is the core competitive advantage different from ordinary raw steel suppliers only supplying flat sheets. According to customer’s engineering drawings, we provide precision laser cutting, flame cutting, numerical control bending, grooving and blanking service. Before heat treatment, raw sheet is processed into near-net-size semi-finished products directly, helping clients save outsourcing processing cost, reduce intermediate turnover loss and shorten production cycle.

Standard 2B surface sheets are attached anti-scratch PVC film before processing to avoid surface scratch during cutting and bending; finished semi-finished components are packed with soft foam to prevent edge collision damage in long-distance transportation. The whole processing link controls dimensional tolerance strictly to match assembly precision requirement of industrial equipment.

In annealed original state, 420J2 has controllable forming rebound, smooth for conventional cold bending and punching without edge cracking; welding performance is general compared with austenitic steel, so spot welding and argon arc welding are only recommended for non-load structural connection, most finished products adopt mechanical assembly after forming and heat hardening. After quenching treatment, material becomes high rigid and hard, no further cold forming available, customers can flexibly arrange processing sequence: form first then heat treatment according to product craft.

1. Hardware & Cutting Tool Blank: The largest consumption field of 420J2, used for kitchen cutter blank, small industrial cutting tools, scissors and precision spring hardware, high hardness after heat treatment ensures long service life of cutting edge.
2. Mechanical Equipment Fittings: Applied for pump valve core parts, bearing bush auxiliary parts, textile machinery wear-resistant inserts and instrument fixing parts, wear resistance effectively reduces equipment later maintenance replacement frequency.
3. Food & Medical Light Equipment Components: Suitable for low-load food processing machine shell fittings and conventional medical instrument structural parts, moderate rust resistance satisfies dry food workshop operating standard.
4. Mould & Machinery Base Plate: Thin and medium thickness customized sheets processed into small plastic mould inserts, fixture base plate and positioning block, replacing expensive die steel for low-load mould use to control production cost.

Each batch of 420J2 cold rolled sheet is inspected on chemical composition, mechanical hardness and surface flatness before delivery, complete mill test certificate is issued to support industrial project inspection and export customs clearance. Bulk sheets adopt waterproof kraft paper + plastic film whole wrapping, cut small pieces are packed in carton with shockproof filler. We accept small trial order for prototype test and large bulk order for mass production, free sample sheet available for customer hardness test and processing verification.