SUS420J2)

AISI 420B is a martensitic chromium stainless steel. Compared with austenitic or ferritic stainless steels, it can achieve significantly higher yield strength and hardness following heat treatment. This material must be used in a quenched and low-temperature tempered condition, and a bright-polished surface is key to achieving optimum corrosion resistance. If subjected to high-temperature tempering or annealing, its corrosion resistance will decline sharply due to carbide precipitation. This alloy exhibits good resistance in moderately corrosive, non-chloride-containing media. Furthermore, the steel demonstrates good oxidation resistance in oxidising atmospheres at temperatures exceeding 600°C. Through quenching, low-temperature tempering and surface polishing, the optimal combination of strength, hardness and corrosion resistance can be achieved.

DIN EN 10088-1：
Stainless steels - Part 1: List of stainless steels
ASTM A276：
Standard Specification for Stainless Steel Bars and Shapes
ASTM F899：
Standard Specification for Wrought Stainless Steels for Surgical Instruments

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Chemical Composition

Element	C	Mn	P	S	Si	Cr	Ni	Fe
Content (%)	0.26-0.35	≤1.00	≤0.04	≤0.030	≤1.00	12.00-14.00	≤1.00	Balance

Heat Treatment Conditions

Condition	Heating Temperature	Hardness (HRC)
Annealed	/	≤235（HBW）
Quenched and tempered	Q 1900℉/1038℃ T 300℉/149℃+	≥49（HRC）

Supply Forms

Available Form	Size Range	Surface Finish	Length (Customizable)	Tolerance (Customizable)	Delivery Condition
Plate	T0.5-T200.0mm	Milled / Bright	L:200/250/300W:200/300/500/1000	-0.0/+1.0mm	Annealed
Bar	φ1.0-φ200.0mm	Ground / Precision Polished	3M/PCS	h6-h9	Annealed
Wire	φ1.0-φ3.0mm	Ground / Precision Polished	1M/PCS	h6-h9	Annealed
Tube	OD：1.0-10.0mmID:0.08mm-2.0mm	Ground / Precision Polished	3M/PCS	h6-h9	Annealed

Datasheet

Additional Info

A Brief History of 420B Stainless Steel

420B stainless steel is a heat-treatable martensitic stainless steel within the 420 series; common designations include AISI 420B, EN 1.4028, X30Cr13 and JIS SUS420J2.

Compared to low-carbon 420-type stainless steels, 420B has a higher carbon content and can achieve greater hardness following heat treatment. Typical 420B / 1.4028 materials have a carbon content of approximately 0.26–0.35% and a chromium content of approximately 12.0–14.0%.

This composition provides 420B with a practical balance between hardness, wear resistance, edge retention and moderate corrosion resistance. It is suitable for components that are first machined in a softer condition and then heat-treated to achieve their final service hardness, such as cutting tools, surgical instruments, dental tools, shaft components, pins and wear-resistant parts.

How was the 420B developed

420B was developed to enhance the hardness and wear resistance of standard 420 stainless steel.

Standard 420 can itself be hardened through heat treatment, but certain tool and instrument components require better edge retention and greater wear resistance. By increasing the carbon content, the hardenability of 420B is enhanced, allowing for higher service hardness to be achieved after quenching and tempering.

Following appropriate heat treatment, 420B / 1.4028 grade stainless steel typically achieves a hardness of approximately 45–51 HRC, depending on the material’s cross-sectional dimensions, heat treatment condition and product specifications.

Consequently, 420B is a suitable material choice when the hardness of standard 420 is insufficient, yet higher-carbon grades such as 440B or 440C are not required.

Early applications of 420B

420B was initially used primarily for components where the hardness or machinability of standard 420 stainless steel was insufficient.

Early applications included blades, cutting tools, surgical instruments, dental tools, small shaft components, pins, valve components and precision mechanical parts.

These components typically require a combination of hardness, wear resistance and practical corrosion resistance. Consequently, 420B is used in the manufacture of reusable tools, cutting components and small mechanical parts.

Current applications of 420B

Today, 420B stainless steel is primarily used in medical instruments, dental instruments, cutting components, precision mechanical parts and industrial wear-resistant components.

Common applications include:

Medical instruments: surgical instruments, scissors, blades, forceps components and reusable instrument parts.

Dental instruments: dental instruments, drive tools, cutting tools and small precision parts.

Mechanical engineering components: shaft components, pins, valve components, pump parts, and precision machined parts requiring hardness and dimensional stability.

Industrial applications: cutting tools, nozzles, valve seats, wear-resistant components, and parts subjected to sliding contact or repetitive motion.

420B is not typically used as a material for implantable medical devices, nor is it suitable for highly corrosive environments. If a project requires long-term contact with the human body, higher corrosion resistance or better biocompatibility, materials such as 316LVM, Grade 23 titanium or cobalt-based alloys should be considered.

Sunxin’s 420B Stainless Steel Supply Support

Sunxin supplies 420B stainless steel to customers requiring martensitic stainless steel materials, suitable for medical instruments, dental instruments, precision components, cutting parts and wear-resistant applications.

The material can be discussed in accordance with AISI 420B, EN 1.4028, X30Cr13, JIS SUS420J2 or customer-specified standards. As there may be differences in grade nomenclature and correspondences across different standard systems, we can assist customers in confirming the required grade, chemical composition, delivery condition, target hardness and end-use requirements prior to supply.

Available forms can include bars, plates, tubes, wire and custom cut sizes, depending on project requirements. Dimensions, tolerances, surface finishes, heat treatment conditions, hardness ranges and quality documentation can be confirmed according to project needs.

For projects requiring material verification, Sunxin can assist in arranging chemical composition analysis, hardness testing, mechanical property testing, dimensional inspection and heat treatment condition verification prior to machining, production or end use.

Whether you require 420B stainless steel for surgical instruments, dental tools, cutting components, shaft parts, pins or wear-resistant components, Sunxin can help you match the appropriate material form, delivery condition and specification requirements to your application needs.

FAQs

Is 420B suitable for medical devices?

Can 420B be used for implants?

What is the difference between 420A and 420B?

What is the difference between 420B and 420Mod?

What is the difference between 420B and 440C?

Does 420B require heat treatment?

Can 420B be polished?

Is 420B corrosion-resistant?

Is 420B magnetic?

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