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Stainless Steel SUS420

Hardenable martensitic stainless steel designed for 3D printed tools and wear parts needing post-heat treatment hardness and abrasion resistance.

SUS420 3D Printing Materials Introduction

Stainless Steel SUS420 is a high-carbon martensitic stainless steel known for its excellent hardness, abrasion resistance, and moderate corrosion resistance after heat treatment. It is widely used in applications requiring sharp edges, impact strength, and dimensional stability.

Through stainless steel 3D printing, SUS420 enables the production of complex wear parts, molds, surgical tools, and high-performance mechanical components with post-print hardening for demanding environments.

SUS420 Similar Grades Table

Country/Region	Standard	Grade or Designation
USA	ASTM	420
UNS	Unified	S42000
ISO	International	X20Cr13
China	GB/T	2Cr13
Germany	DIN/W.Nr.	1.4021

SUS420 Comprehensive Properties Table

Category	Property	Value
Physical Properties	Density	7.75 g/cm³
	Melting Point	1450–1510°C
	Thermal Conductivity (100°C)	24.9 W/(m·K)
	Electrical Resistivity	55 µΩ·cm
Chemical Composition (%)	Iron (Fe)	Balance
	Chromium (Cr)	12.0–14.0
	Carbon (C)	0.15–0.40
	Manganese (Mn)	≤1.0
	Silicon (Si)	≤1.0
Mechanical Properties	Tensile Strength (hardened)	≥850 MPa
	Yield Strength (0.2%)	≥600 MPa
	Hardness (HRC, heat treated)	48–56
	Elongation at Break	≥12%
	Modulus of Elasticity	200 GPa

3D Printing Technology of SUS420

SUS420 is compatible with Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), and Binder Jetting. These technologies enable rapid fabrication of high-hardness parts with intricate features and tight tolerances.

Applicable Process Table

Technology	Precision	Surface Quality	Mechanical Properties	Application Suitability
SLM	±0.05–0.2 mm	Excellent	Excellent (post-hardened)	Cutting Tools, Surgical Parts
DMLS	±0.05–0.2 mm	Very Good	Excellent	Mechanical Assemblies, Molds
Binder Jetting	±0.1–0.3 mm	Moderate	Good (with HIP)	Large Structural Wear Components

SUS420 3D Printing Process Selection Principles

SLM is preferred for tool components and blades where high hardness and dimensional accuracy (±0.05 mm) are critical.

DMLS delivers balanced surface quality and strength, ideal for functional mechanical parts with moderate wear exposure.

Binder Jetting is suitable for large, complex forms followed by HIP and quenching to enhance density and toughness.

SUS420 3D Printing Key Challenges and Solutions

High carbon content can lead to cracking during cooling. Controlled preheat and optimized scan strategy minimize thermal shock during the printing process.

To achieve target hardness (HRC 50+), parts must be quenched at 980–1050°C and tempered at 150–200°C for stress relief and microstructure refinement.

Surface roughness can impair tool cutting edges. Post-processing via CNC machining and grinding is essential to sharpen features and enhance durability.

For improved corrosion resistance, passivation and protective coatings are applied, especially for humid or medical environments.

Typical Post-Processing for SUS420 3D Printed Parts

Quenching and Tempering significantly increases hardness and wear resistance for tools and load-bearing parts.

CNC Machining ensures critical dimensional precision and edge accuracy in cutting and mechanical components.

Grinding or Polishing enhances surface quality and prepares contact areas for dynamic interfaces and wear zones.

Passivation improves oxidation resistance, extending component life in mildly corrosive and moisture-exposed environments.

Industry Application Scenarios and Cases

SUS420 is widely used in:

Tooling and Cutting: Blades, drill bits, punches, and precision guides with hardened edges.
Medical Devices: Surgical scissors, scalpels, and orthopedic instrument components requiring biocompatibility and high hardness.
Industrial Machinery: Bushings, cams, and support elements exposed to friction and abrasive contact.
Energy Sector: Wear-resistant valves, nozzles, and rotating shafts in turbines and pumps.

One tooling case used SLM-printed SUS420 cutting dies post-heat treated to HRC 52, achieving 40% longer tool life and reduced machining waste.