AISI 420 X20Cr13 1.4021 SUS420J1 Martensitic Stainless Steel

Product Overview

AISI 420 stainless steel is a premium martensitic stainless steel renowned for its exceptional combination of moderate corrosion resistance, high strength, and impressive hardness. This versatile material is widely recognized and standardized across the globe, with equivalent grades in major international standards—making it a reliable choice for industries worldwide. Whether you’re manufacturing precision tools, industrial components, or automotive parts, AISI 420 stainless steel delivers consistent quality and performance that meets the demands of critical applications.

Due to its excellent machinability, wear resistance, and ability to be heat-treated for enhanced properties. You can find its equivalents in various international standards, such as: X20Cr13/1.4021 from Europe Standard EN 10088-3, 20Cr13/2Cr13 from China Standard GB/T 1220, SUS420J1 from Japan Standard JIS G4303, 20X13/2X13 from Russia Standard GOST 5632-76.

International Equivalent Grade

AISI 420 stainless steel has established equivalents in key international standards, ensuring compatibility and consistency across global supply chains. Below is a comprehensive breakdown of its counterparts:

This cross-standard compatibility makes AISI 420 a preferred choice for multinational projects, as it simplifies material sourcing and ensures adherence to global quality requirements.

Product Features

Chemical Composition of 420 Steel

The chemical composition of AISI 420 and its equivalent grades is carefully balanced to achieve optimal mechanical and corrosion-resistant properties:

The high chromium content (12.00-14.00%) is the key contributor to the material’s corrosion resistance, forming a protective oxide layer on the surface. The controlled carbon content ensures the steel can be heat-treated to achieve the desired hardness and strength for specific applications.

Mechanical Properties of 420 Steel

AISI 420 and its equivalent grades exhibit excellent mechanical properties, with variations based on the standard and heat treatment condition. Below are the key mechanical specifications:

GB/T 1220 & JIS G4303

Mechanical properties for 20Cr13/2Cr13 from standard GB/T1220 and SUS420J1 from JIS G4303.

EN 10088-3 for X20Cr13 / 1.4021

Mechanical properties for X20Cr13/1.4021 from standard EN10088-3.

A=Annealed; QT=Quenched and tempered

High-Temperature 0.2% Proof Strength (EN 10088-3)

For applications involving elevated temperatures, the minimum 0.2% proof strength of X20Cr13 / 1.4021 (quenched and tempered) is as follows:

QT = quenched and tempered

These properties make AISI 420 suitable for both ambient and moderate high-temperature applications, providing reliable performance under varying stress conditions.

Supply Size & Tolerance & Stock Information

We offer AISI 420 stainless steel in a wide range of product types, sizes, and surface finishes to meet diverse customer needs. Our flexible supply options ensure you get the exact specifications required for your project.

Product Size Range & Length

Surface Finish & Tolerance

In-Stock Sizes

We maintain a large inventory of AISI 420 stainless steel, with monthly stocks of hot rolled and forged bars exceeding 10,000 tons. Below are our regular stock diameters (subject to daily updates):

Hot Rolled Bar Stock Diameters (mm)

10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 120, 130, 140, 150, 160, 170, 180, 190

Hot Forged Bar Stock Diameters (mm)

200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400

Note: Stock availability changes daily. For the latest stock information or custom size requests, please contact our sales team.

Quality Control: Ultrasonic Testing

To ensure the highest quality and reliability of our AISI 420 stainless steel, all products undergo strict ultrasonic testing in accordance with international standards:

• EN 10228-3 Class III

• Sep 1921-84 D/D

This non-destructive testing method detects internal defects such as cracks, inclusions, or porosity, guaranteeing that our steel meets the most demanding quality requirements for critical applications.

Steel Making & Forging Process

We adhere to advanced production processes to manufacture AISI 420 stainless steel with consistent quality and performance:

Steel Making Process

We offer multiple steel making routes to meet specific customer needs:

• EF + LF + VD

• EAF + LF + VD

• EF + LF + VD + ESR

• EAF + LF + VD + ESR

The ESR (Electroslag Remelting) process is optional for applications requiring ultra-pure steel with minimal impurities, ensuring superior mechanical properties and corrosion resistance.

Forging Process

• Hot forging temperature: 800-1100℃ (must not exceed 1100℃ to prevent grain coarsening and δ ferrite formation, which can degrade mechanical properties)

• Cooling method: Slow cooling (furnace cooling or sand cooling) to avoid thermal stress and ensure uniform microstructure

Our forging process is optimized to enhance the steel’s strength, toughness, and dimensional stability, making it suitable for high-load and precision applications.

Heat Treatment

AISI 420 stainless steel responds well to heat treatment, allowing customization of its mechanical properties to suit specific application requirements. Below are the recommended heat treatment procedures:

Annealing

Annealing is used to reduce hardness, improve machinability, and relieve internal stresses. Two common annealing methods:

• Heat the steel to 800-900℃, cool in the furnace at a rate of ≤30°C/h to below 600°C, then air cool. Slow cooling is critical to prevent martensite reformation and hardness recovery.

• Heat the steel to 750℃, cool in the furnace or air (simpler process for less critical applications).

Quenching and Tempering (QT)

Quenching and tempering are used to achieve high strength, hardness, and toughness:

• Quenching: Heat the steel to 920-980℃, cool in oil to achieve a martensitic microstructure.

• Tempering: Reheat the quenched steel to 600-750℃, then quick cool. This step reduces brittleness while retaining high strength and hardness.

The choice of heat treatment depends on the desired final properties—our technical team can provide tailored recommendations based on your application.

Applications

AISI 420 stainless steel unique combination of hardness, wear resistance, and corrosion resistance makes it ideal for a wide range of applications across multiple industries:

1. Knives and Cutting Tools

• Kitchenware: Chef’s knives, fruit knives, scissors, and other food preparation tools (resistant to food acids and easy to sharpen)

• Medical Instruments: Scalpels, dental tools, and surgical instruments (biocompatible, easy to sterilize, and corrosion-resistant)

• Industrial Knives: Paper cutters, razor blades, mold punches, and cutting blades for textiles, plastics, or metals (excellent wear resistance for long service life)

2. Machinery and Industrial Parts

• Bearings and Shafts: High-strength and wear-resistant components for rotating machinery

• Pump and Valve Parts: Valve seats, pump shafts, and seals (resistant to corrosion from fluids and high pressure)

• Molds: Plastic injection molds, die-casting molds, and mold inserts (good machinability and dimensional stability)

3. Automotive & Aerospace

• Automotive Fuel System Parts: Fuel nozzles, fuel pump components, and fuel injector parts (resistant to fuel corrosion and high temperatures)

• Aerospace Components: Non-load-bearing structural parts such as fasteners, brackets, and fittings (lightweight, strong, and corrosion-resistant in harsh environments)

4. Other Applications

• Marine Hardware: Boat fittings, fasteners, and small components (resistant to saltwater corrosion)

• Construction: Decorative hardware, handrails, and precision components (combines functionality with aesthetic appeal)

• Agricultural Equipment: Cutting blades and wear parts (tough and resistant to outdoor elements)

How to Select 420 Stainless Steel for Your Project?

Before making a selection, please consider the following key factors:

• Final Performance Requirements: Do you require higher hardness (>50 HRC) or better toughness? This will determine the necessary heat treatment process.

• Corrosion Environment: It is suitable for general atmospheric conditions, fresh water, and mildly acidic environments. However, it is not recommended for use in high-chloride environments (e.g., seawater) or strong acid/alkali conditions.

• Manufacturing Sequence: Perform all cutting, stamping, and other cold-working operations first, followed by the final heat treatment and polishing.

• Alternative Materials: If higher corrosion resistance is needed, consider AISI 440C. If better toughness is required, consider AISI 410.

Frequently Asked Questions (FAQ)

Q1: What is the main difference between AISI 420 and other stainless steel grades like 304 or 440?

A1: AISI 420 is a martensitic stainless steel, while 304 is austenitic and 440 is a higher-carbon martensitic grade. Key differences:

• 304 offers better corrosion resistance but lower hardness and strength (not heat-treatable to high hardness).

• 440 has higher carbon content, providing superior hardness and wear resistance but lower corrosion resistance compared to 420.

• AISI 420 balances moderate corrosion resistance with high strength/hardness, making it ideal for applications requiring both cutting performance and durability.

Q2: Is AISI 420 stainless steel rust-resistant?

A2: Yes, AISI 420 has moderate corrosion resistance due to its 12-14% chromium content, which forms a protective oxide layer on the surface. It resists rust in most ambient environments, fresh water, and mild chemical exposures. However, it is not suitable for prolonged exposure to saltwater or highly corrosive chemicals (for such applications, consider austenitic grades like 316).

Q3: Can AISI 420 be welded?

A3: AISI 420 can be welded, but it requires preheating (to 200-300℃) and post-weld annealing to prevent cracking and relieve internal stresses. Welding should be performed using low-hydrogen electrodes or filler metals compatible with martensitic stainless steels.

Q4: Can I request custom sizes or surface finishes?

A4: Yes, we offer custom manufacturing for AISI 420 stainless steel, including custom diameters, lengths, thicknesses, and surface finishes (e.g., custom polishing, coating). Contact our sales team with your specific requirements, and we will provide a tailored solution.

Q5: Is AISI 420 suitable for food contact applications?

A5: Yes, AISI 420 is safe for food contact applications (e.g., kitchen knives, food processing tools) as it is non-toxic and resistant to food acids. It complies with food safety standards such as FDA 21 CFR Part 175.300.

Hunan Qilu specializes in providing various hot-forged, hot-rolled, cold-drawn steel products and custom forgings. We are committed to becoming your trusted metal materials partner through reliable quality, extensive inventory, and professional technical support.

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