Stainless Steel S42010
UNS S42010
S42010 (420 Mod) is a molybdenum-modified 420-type martensitic stainless, hardenable by quench and temper to 28-34, 38-44, 48-52 or 52-56 HRC.
Reference datasheet — S42010 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
S42010 tempers and conditions
S42010 is supplied in 6 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault Annealed (soft annealed / mill annealed bar) | Standard stocked condition for machining and forming before customer hardening. | 450 | 760 | 20 | 20 HRC | — |
Cold drawn | Pick for straight, close-tolerance bar with higher as-supplied strength for parts finished without hardening. | 690 | 860 | 13 | 26 HRC | — |
Hardened and high-temperature tempered | Choose for shafts and structural parts needing toughness and moderate strength rather than wear resistance. | 800 | 1,000 | 15 | 31 HRC | — |
Hardened and tempered ~450–540 °C | Compromise hardness for valve stems and pump parts; avoid long holds in the 475 °C embrittlement range. | 1,100 | 1,350 | 11 | 41 HRC | — |
Hardened ~1030–1065 °C, tempered 200–300 °C | Standard service condition for wear parts, valve trim and blades needing hardness plus corrosion resistance. | 1,450 | 1,720 | 7 | 50 HRC | — |
Hardened with cryogenic treat, tempered 150–200 °C | Maximum hardness condition for cutlery edges and severe abrasion; lowest toughness and most sensitive to grinding cracks. | 1,620 | 1,930 | 4 | 54 HRC | — |
What is S42010?
S42010 (420 Mod) is a molybdenum-modified 420-type martensitic stainless, hardenable by quench and temper to 28-34, 38-44, 48-52 or 52-56 HRC. Engineers use it where wear resistance and moderate corrosion resistance are both required, in annealed and cold-drawn bar with default values of 450 MPa yield, 760 MPa tensile, 20% elongation and 225 HB (20 HRC). Corrosion resistance is well below austenitic grades (score 38), service is capped at 400 °C, and the alloy is air-hardening and crack-prone when welded. Standard S42000 is the cheaper substitute when the extra hardness is not needed. S42010 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,454°C (2,649 °F). S42010 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
What is S42010 used for?
- Surgical and dental instruments
- Cutlery and blades
- Bearings and valve parts
- Wear-resistant tooling
Advantages
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Polishes to a fine finish — 85/100, better than 97% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
Limitations
- Needs corrosion protection — 38/100, worse than 95% of stainless steel grades
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
S42010 properties
Typical room-temperature values for S42010-Annealed; bars are the position among stainless steel grades.
Physical3
S42010 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,454°C (2,649 °F).
Mechanical16
S42010 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S42010 is rated for continuous service to 400°C (752 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
S42010 conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 95% of stainless steel grades.
Sustainability4
Producing a kilogram of S42010 takes about 53 MJ of energy and emits 4.3 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 55%.
Manufacturability8
S42010's machinability is fair (45/100, better than 84% of stainless steel grades); weldability poor (25/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. S42010 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S42010
Is S42010 easy to machine?
Machine in the annealed condition with sharp, rigid, positive-rake carbide tooling, heavy feeds and generous coolant; above ~45 HRC switch to grinding, CBN or EDM.
Can S42010 be welded?
Air-hardening and crack-prone — preheat 200–300 °C, use 410/410NiMo filler, keep interpass hot and temper immediately after welding; welding of hardened parts is not recommended.
Can S42010 be formed, bent or molded?
Only light cold forming in the annealed state with generous bend radii; hot work at 1050–1200 °C and slow-cool or full anneal at 840–900 °C before machining.
S42010 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Chardening carbon | 0.15 – 0.3 | 0.22 |
| Mn | ≤ 1 | 0.6 |
| Si | ≤ 1 | 0.4 |
| Pimpurity | ≤ 0.04 | |
| Simpurity | ≤ 0.03 | |
| Cr | 13.5 – 15 | 14.2 |
| Nitoughness / hardenability | 0.4 – 1 | 0.7 |
| Mopitting resistance and temper strength | 0.4 – 1 | 0.7 |
| Fe | balance |
What surface finishes work on S42010?
Passivate per ASTM A967 (nitric or citric) after machining for full corrosion resistance; takes a fine mirror polish and accepts hard chrome, PVD or black oxide, but avoid tempering/bake above 300 °C on low-tempered parts.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel S42010 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 420 ModS42000
How much does S42010 cost?
S42010 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S42010 — frequently asked
What is S42010 used for?
S42010 is typically used for surgical and dental instruments, cutlery and blades, bearings and valve parts and wear-resistant tooling. In short: harder than standard 420; mo-modified corrosion edge; four Q&T hardness bands.
What is the yield strength of S42010?
S42010 has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is S42010 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Machine in the annealed condition with sharp, rigid, positive-rake carbide tooling, heavy feeds and generous coolant; above ~45 HRC switch to grinding, CBN or EDM.
Can S42010 be welded?
Not readily — weldability is rated poor (25/100). Air-hardening and crack-prone — preheat 200–300 °C, use 410/410NiMo filler, keep interpass hot and temper immediately after welding; welding of hardened parts is not recommended.
What surface finishes work on S42010?
Passivate per ASTM A967 (nitric or citric) after machining for full corrosion resistance; takes a fine mirror polish and accepts hard chrome, PVD or black oxide, but avoid tempering/bake above 300 °C on low-tempered parts.
Can S42010 be formed, bent or molded?
Only light cold forming in the annealed state with generous bend radii; hot work at 1050–1200 °C and slow-cool or full anneal at 840–900 °C before machining.
What is the maximum service temperature of S42010?
S42010 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S42010 Annealed and S42010-CD?
Annealed is the default condition — standard stocked condition for machining and forming before customer hardening. CD: pick for straight, close-tolerance bar with higher as-supplied strength for parts finished without hardening. Yield strength is 450 MPa in Annealed versus 690 MPa in CD.
How much does S42010 cost?
S42010 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A276/A276M Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A473 Stainless Steel Forgings — ASTM International (2020)
- SAE J1086 / UNS Numbering of Metals and Alloys — SAE International (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- Martensitic stainless bar (420 modified, Mo-bearing) technical data — Crucible / Universal Stainless (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.