Stainless Steel 40Kh13
EN 40Kh13 · AISI/SAE 420
40Kh13 is a Russian/CIS martensitic stainless steel equivalent to AISI 420, with about 13% chromium and enough carbon to harden by quench and temper.
Reference datasheet — 40Kh13 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 A condition
40Kh13 tempers and conditions
40Kh13 is supplied in 8 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stock condition for bar, strip and forging blanks — machine and form here, then harden. | 420 | 700 | 20 | 200 HB | — |
Hot rolled | Mill condition of hot bar and billet — hard and partly martensitic, normally annealed before machining. | 600 | 880 | 12 | 26 HRC | — |
Cold drawn | Choose for tight-tolerance ground/drawn bar and spring wire that will be hardened after machining. | 720 | 900 | 10 | 27 HRC | — |
Q&T 600–680 °C | Structural condition for shafts, valve stems and fasteners where toughness and machinability matter more than hardness. | 780 | 980 | 14 | 30 HRC | — |
Cold Rolled Hard strip | Precision strip supplied work-hardened for stamped blades and shims that are hardened after blanking. | 1,050 | 1,250 | 4 | 41 HRC | 2.8 % IACS |
Q&T 400–500 °C | Spring, blade-back and valve-plate condition; accept the reduced impact toughness of the 475 °C embrittlement window. | 1,250 | 1,500 | 8 | 46 HRC | — |
Q&T 150–300 °C | The cutlery / surgical-instrument condition: maximum hardness, edge retention and corrosion resistance after polishing. | 1,450 | 1,750 | 5 | 51 HRC | — |
As-Quenched | Intermediate condition only — must be tempered or stress-relieved immediately to avoid quench cracking. | 1,550 | 1,950 | 2 | 55 HRC | — |
What is 40Kh13?
40Kh13 is a Russian/CIS martensitic stainless steel equivalent to AISI 420, with about 13% chromium and enough carbon to harden by quench and temper. Engineers select it for surgical instruments, cutlery and springs, and it is supplied as bar, flat and strip in annealed, hot-rolled, cold-drawn and QT200/QT400/QT600 conditions. Annealed stock gives 420 MPa yield, 700 MPa tensile, 20% elongation and 200 HB (94 HRB), with service to 550 °C. Corrosion resistance is moderate (score 40) and weldability is poor; for higher hardness and wear life step up to 95Kh18/440C. 40Kh13 has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,425°C (2,597 °F). 40Kh13 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 215 GPa (31.2 Msi).
What is 40Kh13 used for?
- surgical instruments
- cutlery
- springs
- measuring tools
Advantages
- Conducts heat well — 28.5 W/m·K (16.5 BTU/hr·ft·°F), better than 97% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
Limitations
- Needs corrosion protection — 40/100, worse than 93% of stainless steel grades
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
40Kh13 properties
Typical room-temperature values for 40Kh13-A; bars are the position among stainless steel grades.
Physical3
40Kh13 has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
40Kh13 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
40Kh13 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 28.5 W/m·K (16.5 BTU/hr·ft·°F), better than 97% of stainless steel grades. Thermal expansion is 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
40Kh13 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 93% of stainless steel grades.
Sustainability4
Producing a kilogram of 40Kh13 takes about 53 MJ of energy and emits 4.5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
40Kh13's machinability is fair (45/100, better than 84% of stainless steel grades); weldability poor (25/100); formability fair (40/100).
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. 40Kh13 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 40Kh13
Is 40Kh13 easy to machine?
Machine in the annealed state with sharp, positive-rake carbide, rigid setups and generous coolant; above ~40 HRC switch to grinding, CBN or EDM.
Can 40Kh13 be welded?
Poor weldability — preheat 200–300 °C, use 410NiMo or austenitic filler, and temper/anneal immediately after welding to avoid cracks in the hard HAZ.
Can 40Kh13 be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii (≥2t); hot work at 1100–850 °C followed by slow cooling and full anneal.
40Kh13 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 |
|---|---|---|
| C | 0.36 – 0.45 | 0.4 |
| Si | ≤ 0.8 | 0.4 |
| Mn | ≤ 0.8 | 0.4 |
| Cr | 12 – 14 | 13 |
| Niresidual | ≤ 0.6 | |
| Tiresidual | ≤ 0.2 | |
| Curesidual | ≤ 0.3 | |
| S | ≤ 0.03 | |
| P | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 40Kh13?
Harden and temper before final polishing, then passivate in nitric or citric acid; hard chrome, PVD or black oxide are common on cutlery and instruments.
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 40Kh13 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- AISI / SAE
- 420
How much does 40Kh13 cost?
40Kh13 is a standard-cost stainless steel ($$), cheaper than about 71% 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.
40Kh13 — frequently asked
What is 40Kh13 used for?
40Kh13 is typically used for surgical instruments, cutlery, springs and measuring tools. In short: hardenable 420-type stainless; edge-holding instrument grade; poor weldability.
What is the yield strength of 40Kh13?
40Kh13 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 64% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is 40Kh13 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Machine in the annealed state with sharp, positive-rake carbide, rigid setups and generous coolant; above ~40 HRC switch to grinding, CBN or EDM.
Can 40Kh13 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability — preheat 200–300 °C, use 410NiMo or austenitic filler, and temper/anneal immediately after welding to avoid cracks in the hard HAZ.
What surface finishes work on 40Kh13?
Harden and temper before final polishing, then passivate in nitric or citric acid; hard chrome, PVD or black oxide are common on cutlery and instruments.
Can 40Kh13 be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii (≥2t); hot work at 1100–850 °C followed by slow cooling and full anneal.
What is the maximum service temperature of 40Kh13?
40Kh13 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 40Kh13-A and 40Kh13-Q?
A is the default condition — standard stock condition for bar, strip and forging blanks — machine and form here, then harden. Q: intermediate condition only — must be tempered or stress-relieved immediately to avoid quench cracking. Yield strength is 420 MPa in A versus 1,550 MPa in Q.
How much does 40Kh13 cost?
40Kh13 is a standard-cost stainless steel ($$), cheaper than about 71% 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
- GOST 5632-2014 Stainless steels and corrosion-resistant alloys — grades — Rosstandart (2014)
- GOST 5949-2018 Corrosion-resistant, heat-resistant steel bars and sections — Rosstandart (2018)
- GB/T 1220 (40Cr13) — SAC (2007)
- ASTM A276/A276M Stainless Steel Bars and Shapes (UNS S42000) — ASTM (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Marochnik stali i splavov — 40Х13 physical and mechanical data — Marochnik (2020)
- 1.4034 / X46Cr13 martensitic stainless datasheet — Böhler / Outokumpu (2021)
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.