Steel 37Cr4
EN 37Cr4
37Cr4 (1.7034, SAE 5135) is a chromium through-hardening steel from the EN 10083-3 family, with slightly more carbon than 34Cr4 for greater strength after heat treatment.
Reference datasheet — 37Cr4 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 +QT condition
37Cr4 tempers and conditions
37Cr4 is supplied in 10 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold heading, cold extrusion of fasteners and for the best drill/tap behaviour before hardening. | 350 | 580 | 25 | 180 HB | — |
Annealed | Softest supply condition for heavy machining or as a pre-condition before hardening. | 380 | 620 | 22 | 200 HB | — |
Treated to ferrite-pearlite structure and hardness range | Ordered when a specified machining hardness band with a controlled F/P microstructure is needed for automatic machining lines. | 400 | 660 | 20 | 14 HRC | 8 % IACS |
Normalized | Uniform fine ferrite-pearlite structure for stock removal, forging clean-up and stress relief before final Q&T. | 420 | 700 | 19 | 210 HB | — |
+QT | Heavier bar/forging class; reduced core strength because 37Cr4 hardenability limits full martensite above ~40 mm. | 450 | 720 | 19 | 18 HRC | — |
+QTDefault Quenched and tempered | Standard stocked condition: balanced strength and toughness for shafts, connecting rods and highly loaded machine parts. | 520 | 780 | 17 | 22 HRC | — |
Induction hardened | Pick when a wear-resistant 50–56 HRC surface and compressive residual stress are needed over a tough Q&T core (journals, splines, cams). | 540 | 800 | 15 | 53 HRC | — |
Cold drawn | Bright cold-drawn bar with close tolerance and higher as-supplied strength for shafts machined without further heat treatment. | 620 | 760 | 10 | 230 HB | — |
+QT | Highest EN 10083-3 property class for small-diameter bar, pins and bolts where full through-hardening is achieved. | 700 | 920 | 15 | 29 HRC | — |
Specified hardenability band / hardened | Order +H when the Jominy hardenability band must be guaranteed; as-quenched (830–870 °C, oil) it reaches full martensitic hardness and must be tempered before service. | 1,400 | 1,800 | 3 | 54 HRC | — |
What is 37Cr4?
37Cr4 (1.7034, SAE 5135) is a chromium through-hardening steel from the EN 10083-3 family, with slightly more carbon than 34Cr4 for greater strength after heat treatment. In the default condition it gives about 520 MPa yield, 780 MPa tensile, 17 % elongation and 235 HB (22 HRC) and can be used to about 400 °C; it is stocked as bar and forging stock in +A, +AC, +N, +FP and section-graded +QT tempers, plus induction-hardened variants. It is not corrosion resistant and weldability is limited (CE ≈ 0.65–0.70), requiring preheat and post-weld tempering. 41Cr4 is the next step up when higher tensile strength is needed. 37Cr4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). 37Cr4 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 67% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
What is 37Cr4 used for?
- shafts
- gears
- axles
Limitations
- Limited formability — 22/100, worse than 76% of steel grades
37Cr4 properties
Typical room-temperature values for 37Cr4-+QT; bars are the position among steel grades.
Physical3
37Cr4 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
37Cr4 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 67% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
37Cr4 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
37Cr4 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 37Cr4 takes about 28 MJ of energy and emits 2 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 25%.
Manufacturability8
37Cr4's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (35/100); formability poor (22/100).
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 steel family
Yield strength against density for every steel grade FabDigit runs. 37Cr4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 37Cr4
Is 37Cr4 easy to machine?
Machine in +A/+AC or +FP condition (≈60–70% of 1212); in +QT at 235 HB use coated carbide, moderate speed and rigid setup, finish-grind after hardening.
Can 37Cr4 be welded?
CE ≈ 0.65–0.70 — preheat 200–300 °C, low-hydrogen consumables, and temper/stress-relieve at 550–650 °C after welding; avoid welding in the hardened condition.
Can 37Cr4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold heading only in the spheroidized +AC condition, bending in +QT is limited to large radii.
37Cr4 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 | 0.34 – 0.41 | 0.37 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| Cr | 0.9 – 1.2 | 1.05 |
| Pmax per EN 10083-3 | ≤ 0.03 | 0.02 |
| S0.020–0.040 for +S free-machining variants | ≤ 0.04 | 0.02 |
| Fe | balance |
What surface finishes work on 37Cr4?
Not corrosion resistant — protect with phosphate + oil, black oxide, zinc/zinc-nickel plating, hard chrome, or nitriding for wear; grind and polish easily to Ra < 0.4 µm.
Surface treatments FabDigit runs on 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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 37Cr4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.7034
- Similar grades
- 5135
How much does 37Cr4 cost?
37Cr4 is a budget-cost steel ($), cheaper than about 90% 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.
37Cr4 — frequently asked
What is 37Cr4 used for?
37Cr4 is typically used for shafts, gears and axles. In short: higher-carbon 34Cr4 upgrade; Q&T automotive shaft steel; takes induction hardening.
What is the yield strength of 37Cr4?
37Cr4 has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 37Cr4 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in +A/+AC or +FP condition (≈60–70% of 1212); in +QT at 235 HB use coated carbide, moderate speed and rigid setup, finish-grind after hardening.
Can 37Cr4 be welded?
With care — weldability is rated fair (35/100). CE ≈ 0.65–0.70 — preheat 200–300 °C, low-hydrogen consumables, and temper/stress-relieve at 550–650 °C after welding; avoid welding in the hardened condition.
What surface finishes work on 37Cr4?
Not corrosion resistant — protect with phosphate + oil, black oxide, zinc/zinc-nickel plating, hard chrome, or nitriding for wear; grind and polish easily to Ra < 0.4 µm.
Can 37Cr4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold heading only in the spheroidized +AC condition, bending in +QT is limited to large radii.
What is the maximum service temperature of 37Cr4?
37Cr4 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 37Cr4 +QT and 37Cr4-IH?
+QT is the default condition — standard stocked condition: balanced strength and toughness for shafts, connecting rods and highly loaded machine parts. IH: pick when a wear-resistant 50–56 HRC surface and compressive residual stress are needed over a tough Q&T core (journals, splines, cams). Yield strength is 520 MPa in +QT versus 540 MPa in IH.
How much does 37Cr4 cost?
37Cr4 is a budget-cost steel ($), cheaper than about 90% 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
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10277 Bright steel products — technical delivery conditions — CEN (2018)
- GB/T 3077 (35Cr equivalent) — SAC (2015)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 Fatigue and Fracture — ASM International (1996)
- Chromium quenched and tempered steel 1.7034 data sheet — European long-products mill (typical) (2022)
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.