Suitable for manufacturing high-hardness parts, wear-resistant parts, cutting tools, mold accessories, shaft parts, valve parts, and stainless steel functional parts requiring heat treatment strengthening.
420 Stainless Steel is a martensitic stainless steel material with relatively high hardness, good wear resistance, certain corrosion resistance, and heat-treatable strengthening. Compared to austenitic stainless steels like 304 and 316, 420 has weaker corrosion resistance but better hardness, strength, and wear resistance. It is commonly used in cutting tools, cutting tools, mold parts, valve parts, shaft parts, non-implantable parts of medical devices, hardware, and stainless steel functional parts requiring higher hardness.
By focusing on application scenarios, boundaries of advantages, and non-recommended scenarios, it helps sales, customer service, and quoting staff quickly determine whether the material meets current part requirements.
It has high hardness, good strength, good wear resistance, can be heat-treated for strengthening, is magnetic, suitable for cutting tools and wear-resistant parts, and can be improved by quenching and tempering after processing. Its cost is usually lower than that of high-end corrosion-resistant stainless steel and high-performance mold steel.
Cutting tools, cutting tools, scissor parts, non-implantable parts of medical devices, valve parts, pump shafts, shaft sleeves, mold accessories, wear-resistant connectors, mechanical structural parts, hardware parts, fasteners, nozzles, and high-hardness stainless steel parts in low to moderate corrosive environments.
Highly corrosive environment parts, seawater or high salt spray environment parts, food long-term contact parts, medical implant parts, strong acid and strong alkali environment parts, high-end mirror-finish parts, strong welded structural parts, high toughness and impact-resistant parts, parts requiring non-magnetic materials, and parts requiring corrosion resistance higher than 304 or 316.
The following parameters come from product information and material knowledge fields, used for design review, quotation communication, and preliminary judgment before material selection.
| Material positioning | Suitable for manufacturing high-hardness parts, wear-resistant parts, cutting tools, mold accessories, shaft parts, valve parts, and stainless steel functional parts requiring heat treatment strengthening. |
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| Precision performance | 420 Stainless Steel is suitable for CNC turning, milling, grinding, drilling, tapping, and finishing after heat treatment. In the annealed state, machinability is relatively good; after heat treatment, hardness increases, making machining significantly more difficult. For shaft parts, hole positions, threads, mating surfaces, cutting edges, and wear-resistant surfaces, it is recommended to reserve machining allowance according to the heat treatment sequence and perform grinding or finishing when necessary. |
| Dimensional tolerances | The conventional dimensional tolerances of CNC machining 420 Stainless Steel can be referenced as ± 0.02mm to ±0.10mm, while ordinary structural parts can be evaluated at ±0.10mm-±0.20mm. If a part requires heat treatment, dimensional changes or deformation may occur after heat treatment. It is recommended to heat treat key dimensions before finishing or grinding. This value is a standard reference range and does not guarantee absolute tolerances for all structures. |
| Minimum Wall Thickness | The wall thickness of ordinary CNC machined structures is recommended to be no less than 0.8mm-1.0mm. Small non-load-bearing areas can be further optimized according to structure and processing methods, but large-area designs that are too thin are not recommended. Areas requiring heat treatment, tapping, load-bearing, wear resistance, or forming cutting edges should be appropriately thickened to avoid deformation, cracking, chipping, or insufficient strength. |
| Recommended wall thickness | For ordinary structural parts, 1.5mm-3.0mm is recommended; for shaft parts, tool bodies, mounting seats, threaded connection points, wear-resistant surfaces, and load-bearing positions, 2.0mm or more is recommended; for parts requiring heat treatment, increase machining allowance based on deformation risk and reserve grinding or finishing allowance at key dimensional positions. |
| Minimum aperture | CNC machining can achieve smaller hole diameters, but controlling deep small holes and hole position accuracy after heat treatment is more challenging. For general designs, the recommended aperture is no less than 1.0mm. For precision holes, threaded holes, positioning holes, and fitting holes, it is recommended to reserve machining allowance; if necessary, heat treatment should be followed before drilling, reaming, boring, or grinding. |
| Assembly clearance | For precision metal assembly, one side can be reserved at 0.02mm-0.10mm according to fitting requirements; for ordinary plug-in and assembly, it is recommended to reserve 0.10mm-0.30mm per side. If parts require heat treatment, sandblasting, passivation, anti-rust, or coating treatment, assembly allowance should be increased in conjunction with heat treatment deformation and surface treatment thickness. |
| Detailed performance | 420 Stainless Steel suitable for machining holes, grooves, steps, chamfers, threads, shaft shoulders, positioning surfaces, cutting edges, and wear-resistant structural details. In CNC machining mode, detail performance is good, and after heat treatment, grinding can improve the quality of key surfaces and cutting edges. For fine text, logos, and markings, it is recommended to achieve laser marking, engraving, or etching to avoid designing overly fine and difficult-to-machine mechanical textures under high hardness. |
| Surface effect | 420 Stainless Steel raw processed surface usually has a silver-gray metallic texture, which can be achieved by polishing to achieve a brighter surface, brushing for linear metal textures, and sandblasting for a matte industrial appearance. Since its corrosion resistance is inferior to 304 and 316, if the exterior parts are exposed for long-term use, it is recommended to combine passivation, rust prevention, spraying, or other surface protection treatments. Cutting tools and cutting tool parts usually focus more on edge quality and wear resistance rather than just appearance glossiness. |
Based on material characteristics and suitable product ranges, customer needs are broken down into easier application directions to determine.
Cutting tools, cutting tools, scissor parts, non-implantable parts of medical devices, valve parts, pump shafts, shaft sleeves, mold accessories, wear-resistant connectors, mechanical structural parts, hardware parts, fasteners, nozzles, and high-hardness stainless steel parts in low to moderate corrosive environments.
Suitable for manufacturing high-hardness parts, wear-resistant parts, cutting tools, mold accessories, shaft parts, valve parts, and stainless steel functional parts requiring heat treatment strengthening.
420 Stainless Steel is a martensitic stainless steel, mainly characterized by high hardness and good wear resistance through heat treatment, making it suitable for making tools, cutting tools, shaft parts, and wear-resistant parts. It is magnetic and corrosion resistant superior to ordinary carbon steel, but lower than austenitic stainless steels such as 304, 316, and 316L. 420 leans more toward stainless steel materials that prioritize "hardness and wear resistance" rather than "corrosion resistance."
Based on wall thickness, hole position, assembly clearance, dimensional tolerances, and material usage risks, determine in advance whether the part structure is suitable for 420 Stainless Steel.
Post-processing of 420 Stainless Steel affects appearance, dimensions, hole position, assembly clearance, and usage validation results, and should be explained in advance during quotation, DFM review, and sample confirmation stages.
Post-processing should focus on appearance display, dimensional fitting, connection assembly, and testing verification. Parts involving assembly positions need to be reserved in advance for machining, coating, and trial assembly allowances.
For common issues such as threads, snaps, strength, temperature resistance, and weather resistance, identify in advance whether the material needs to be replaced or if another processing method should be used.
When customer demand exceeds 420 Stainless Steel material boundaries, it is necessary to combine strength, temperature resistance, toughness, long-term stability, and mass production goals to promptly recommend alternative materials or processing technologies.
If better corrosion resistance is required, 304 stainless steel, 316 stainless steel, or 316L stainless steel can be chosen; If better machinability is required, 303 stainless steel can be chosen; If spring clips and elastic structures are needed, 301 stainless steel can be chosen; If higher hardness and wear resistance are required, 440C stainless steel, mold steel, or heat-treated alloy steel can be chosen; If higher toughness and overall mechanical properties are needed, 410, 17-4PH, or other high-strength stainless steels can be considered.
If customers require higher hardness, wear resistance, cutting edges, or strength after heat treatment,420 Stainless Steel is the appropriate choice. If customers are more concerned about corrosion resistance, food equipment, moisture salt spray, or long-term outdoor stability, it is recommended to prioritize 304, 316, or 316L. If customers require high-precision tools, precision wear-resistant parts, or high-hardness long-term friction structures, further confirmation should be made based on heat treatment hardness, surface treatment, and actual wear conditions.
After uploading 3D/2D drawings and supplementing materials, quantities, tolerances, surface treatments, and delivery requirements, XPartsLab will provide next steps in 3D printing manufacturability, cost, and delivery pathways.
