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Grade 420, martensitic stainless steel

420 Stainless Steel Coil and Sheet

A hardenable martensitic stainless steel with at least 12% chromium and more carbon than 410 and 416, for higher strength, hardness and wear resistance. Hardens to about 50 HRC; corrosion resistance is best when hardened and polished.
Tell us about your projectSee sizes
Forms
Coil, sheet
Thickness
0.15–3.0 mm
Width
1000 / 1219 / 1240 / 1500 mm
Also known as
UNS S42000, EN 1.4021, SUS420J1 / SUS420J2

Is Sanmei Metal the right supplier for you?

We supply stainless steel together with the processing and technical support that projects and products need.

A good fit if you

Need a specific grade, finish or size for a project, from samples or one coil to a few containers
Want it slit, cut to size or fabricated to your drawing
Need documents: a Mill Test Report with every order, SGS testing on request
Want help choosing the right grade and finish for your application
Build products or projects: equipment housings, architectural interiors, elevator and kitchen work

When buying direct from a mill may suit you better

You need standard grades in full-mill quantities and compare on price per tonne
Not sure which applies to you? Tell us about your order and we will give you our professional advice.
Tell us about your projectSee what we fabricate

Sizes we supply in 420.

Standard widths from stock, cut-to-length sheet, and custom slitting for strip-fed production lines.

420 coil

Width
1000, 1219, 1240, 1500 mm, or slit to your width
Thickness
0.15–3.0 mm
Coil weight
3–10 t

420 sheet

Width
1000, 1219, 1240, 1500 mm, or cut to size
Length
2000, 2438, 2500, 3000, 3048 mm
Thickness
0.3–3.0 mm
Every order ships with a Mill Test Report. Sample sheets and small batches are welcome. Standard mill finish: 2B finish.
Get a quote for 420Send a cut list or drawing

What 420 is, and where it is used.

A high-carbon martensitic grade with a balance of hardness and corrosion resistance.

General properties

Carbon from 0.15%, chromium 12.0–14.0%, with smaller amounts of manganese, silicon, phosphorus and sulfur. High hardness and wear resistance, moderate corrosion resistance, good ductility when annealed.

Applications

Cutlery, knives, surgical and dental instruments, tools, bushings, pump parts, valve components and shafts, plus precision machinery, bearings, household appliances and food utensils.

Standards

ASTM A240 for plate, sheet and strip, and ASTM A276 for bars. In JIS, it is supplied as SUS420J1 and SUS420J2.

Why 420 for knives and tools

Corrosion resistance

Resists rust in mild, damp and domestic environments, best when hardened and polished.

Strength and hardness

High strength and hardness for tools and instruments under stress and frequent use.

Easy to clean

A smooth, polished surface that does not easily hold dirt, for food processing and medical use.
Tell us what the part is, where it will be used and roughly how many. We confirm the grade and finish before you order.
Tell us your application

Corrosion, heat and the shop floor.

How 420 behaves in service and in fabrication.

Corrosion resistance

Good, especially when hardened and polished, but below the common austenitic grades.

Heat resistance

Limited by loss of ductility at sub-zero temperatures and loss of strength at elevated temperatures through over-tempering. Not recommended above its tempering temperature.

Machining

Relatively easy when annealed; harder once hardened above 30 HRC.

Welding

Not common, given its hardening, but possible with the right technique and post-weld heat treatment to prevent cracking.

Hot working

Improves toughness and wear resistance.

Cold working

Increases hardness and strength, and improves surface quality and dimensional accuracy.

Annealing

Softens the steel, improves machinability and prepares it for further heat treatment.

Hardening and tempering

Harden by heating and quenching, to about 50 HRC; temper to reduce brittleness and internal stress.
Have a drawing, cut list or sample photo? Upload it and we review it and send you a quote.
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420 physical and mechanical properties.

Typical physical values, and mechanical values for annealed plate, sheet and strip (ASTM A240).

Physical properties

Property
Value
Density
7.74 g/cm³
Modulus of elasticity
200 GPa (29 × 10⁶ psi)
Thermal expansion, 0–100 °C
10.3 µm/m·°C (5.7 × 10⁻⁶ /°F)
Thermal conductivity
24.9 W/m·K (14.4 Btu/ft·hr·°F)
Specific heat, 0–100 °C
460 J/kg·K (0.11 Btu/lb·°F)
Electrical resistivity, 20 °C
55 µΩ·cm

Mechanical properties, annealed (ASTM A240)

Property
Value
Tensile strength, max.
690 MPa (100 ksi)
Elongation, min.
15%
Hardness, max.
217 HBW / 96 HRB
Hardness after hardening
about 50 HRC

Chemical composition, % by weight, max. unless a range (ASTM A240)

Grade
C
Mn
Si
P
S
Cr
420
0.15 min.
1.00
1.00
0.040
0.030
12.0–14.0
Tell us what the part is, where it will be used and roughly how many. We confirm the grade and finish before you order.
Tell us your application

Finishes and processing from Sanmei Metal.

Mill finishes, decorative finishes made in our own facility, and coil and sheet cut to your size.

Decorative finishes

Nickel Silver Hairline Stainless Steel Sheet S26HL-01 (3)
Hairline
Nickel Silver Satin Stianless Steel Sheet S26ST-01 (3)
Satin
black mirror polised stainless steel
Mirror
Nickel Silver Vibration Stainless Steel Sheet S26VB-01 (2)
Vibration
See all decorative finishes →

Mill finishes

Processing

Precision slitting
Cut to length
Shearing
Edge trimming
Blanking
Surface polishing
Tell us about your projectSend a sample photo or drawing

420, 420J1 and 420J2.

420J1 and 420J2 are branches of 420, made to meet different needs for hardness, strength and corrosion resistance. Adjusting the composition, above all the carbon, gives steels for different uses.
Tell us what the part is, where it will be used and roughly how many. We confirm the grade and finish before you order.
Tell us your application

The supplier you can trust.

Every order ships with a Mill Test Report.
Click a document to see it full size.
Get a quote with Mill Test Report

420 stainless steel FAQ.

Questions buyers ask before ordering 420.

How hard can 420 get?

About 50 HRC after hardening and tempering. It is supplied annealed for forming and machining.

Is 420 magnetic?

Yes. It is a martensitic stainless steel and it is magnetic.

What is the difference between 420, 420J1 and 420J2?

420J1 and 420J2 are the JIS versions of 420. 420J1 has 0.16–0.25% carbon for better corrosion resistance; 420J2 has 0.26–0.40% carbon for greater hardness.

Is 420 as corrosion resistant as 304?

No. It resists corrosion well, especially when hardened and polished, but less than austenitic grades such as 304.

Can 420 be welded?

It is not commonly welded, but it can be, with the right technique and post-weld heat treatment to prevent cracking.

What sizes do you supply?

Coil in 1000, 1219, 1240 and 1500 mm widths or slit to size, 0.15–3.0 mm thick. Sheet in the same widths, 2000 to 3048 mm long, 0.3–3.0 mm thick.
Question not answered here? Ask us directly and our team will reply in person.
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Why project buyers work with Sanmei Metal

Material-driven, engineering-supported, execution-ready. One supplier from the mill to your site.
1

Source from leading partner mills

Base coil from Lisco, Tisco, Jisco, Posco PZSS, Yongjin and Hongwang, each batch with its Mill Test Report.
Our mill partners
2

Finish in-house

PVD, water plating and surface finishing under one roof at our Foshan facility.
Decorative finishes
3

Engineer and fabricate

Our engineers review drawings so profiles and panels can be made and installed.
Architectural metal works
4

Protect and ship

Film matched to laser cutting or stamping, and crates or steel frames packed for sea freight.
Packing and filming
Technical questions about grades, finishes or tolerances?
Technical guide

Our Leading Coating Technology.

Thicker coating, consistent color and easy-clean surfaces. Each one measured in our own production and compared with typical market product.
PVD coating

Thicker PVD coating

0.30µm
Typical coating thickness, up to 28% thicker than a typical market coil, so the color lasts longer.
See the coating test
Color control

Consistent color

ΔE ≤ 2
Every coil is held below the color difference the eye can see, so panels from different batches match.
See the color data
Anti-fingerprint

Fingerprint-resistant

215solvent rubs
Our anti-fingerprint coating withstood 215 rubs with a strong solvent. The standard requires 100. Typical market AF failed at 70.
See the AF test
Tested to GB/T and ISO standards, with MTR and SGS reports on request.
See all our quality control.

Documents you can check.

Every order ships with a Mill Test Report traced to its heat number, and SGS testing is available on request. These are real documents from our mill partners and our project work.
Certifications shown belong to Sanmei and its fabrication partners. Click a document to see it full size.

Tell us about your project.

Send a drawing, a reference photo or just the grade and size. Our team replies with material advice, finish options, samples and a quote.
What helps us answer fastest
Drawing, sketch or reference photo
Grade and thickness, if you know them
Finish or color you have in mind
Quantity and delivery location
Tell us about your project →
Samples and small batches are welcome.

Contact us

Creating Center, Shunde District, Foshan City, Guangdong Province, 528315, China
+8615015653566 / 0757-87668353
Paige Deng
marketing@sanmeimetal.com

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    TEL: +8615015653566 / 0757-87668353
    Email: marketing@sanmeimetal.com

    Headquarters:
    Creating Center, No.142, Yuhe Road, Lecong Town, Shunde District, Foshan City, Guangdong Province, China. 528315

    Factory: Liyuan Logistics City, Chencun Town, Shunde District, Foshan City, Guangdong Province, China. 528313

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