Steel 4037-HR (Hot rolled)
Supply condition
AISI/SAE 4037 · UNS G40370
Cheapest mill condition for parts that will be heat treated after rough machining or forging.
Values for the HR condition
Other 4037 tempers and conditions
4037 is listed in 8 conditions; see the grade overview at 4037.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRThis page Hot rolled | Cheapest mill condition for parts that will be heat treated after rough machining or forging. | 380 | 620 | 22 | 179 HB | — |
Solution annealed | Softest, most machinable and most formable condition; use before quench and temper or for cold heading stock. | 400 | 585 | 27 | 170 HB | — |
Normalized | Uniform fine-grain structure and mid-range strength for forgings and weld fabrications not requiring full Q&T. | 450 | 690 | 22 | 200 HB | — |
Cold drawn | Close-tolerance bright bar with raised yield strength for shafts and screw-machine work with no further heat treatment. | 585 | 690 | 15 | 200 HB | — |
quenched and tempered, ~250 HB | Toughest Q&T level; choose for shock-loaded shafts and couplings where impact matters more than strength. | 700 | 830 | 20 | 24 HRC | — |
QT-28-32HRCDefault quenched and tempered, ~285 HB | Standard general-purpose condition for machined shafts, studs and high-strength fasteners. | 860 | 965 | 18 | 30 HRC | — |
quenched and tempered, ~320 HB | Higher-strength Q&T level typical of SAE J429 Grade 8 / ASTM A354 BC fastener requirements. | 965 | 1,080 | 15 | 34 HRC | — |
quenched and low-temperature tempered | Maximum-strength condition for small wear parts and pins; reduced ductility and notch sensitivity must be accepted. | 1,240 | 1,380 | 12 | 42 HRC | — |
What is 4037-HR?
4037-HR is 4037 supplied in the HR condition — cheapest mill condition for parts that will be heat treated after rough machining or forging. 4037-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 68% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi). 4037-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). QT-28-32HRC is the default condition FabDigit quotes; HR is available on request or by drawing note.
4037-HR properties
Typical room-temperature values for 4037-HR; 12 are specific to this condition. Other listed values are 4037 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4037-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
4037-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 68% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4037-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
4037-HR conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4037-HR takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
4037-HR's machinability is good (60/100, better than 83% of steel grades); weldability good (55/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4037-HR
Is 4037 easy to machine?
Machine in the annealed or ≤32 HRC Q&T condition with coated carbide, ~120–180 m/min; above 36 HRC expect tool wear and prefer grinding or hard turning with CBN.
Can 4037 be welded?
Weldable with low-hydrogen consumables but the ~0.37 %C requires 200–300 °C preheat, interpass control and post-weld temper/stress relief to avoid HAZ cracking.
Can 4037 be formed, bent or molded?
Cold heading and bending are practical only in the annealed/spheroidized state; hot forge 1200 °C down to ~950 °C then normalize before quench and temper.
What surface finishes work on 4037?
No inherent corrosion resistance — specify zinc, zinc-nickel or chrome plating, black oxide, phosphate-and-oil or paint; bake after plating at ≥190 °C to relieve hydrogen embrittlement above 32 HRC.
4037 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 | 0.35 – 0.4 | 0.37 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Mo | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
4037-HR — frequently asked
What is 4037-HR used for?
4037-HR is typically used for bolts, studs, shafts and gears. In short: strongest 40xx moly grade; wide Q&T hardness range; good strength-to-cost ratio.
What is the yield strength of 4037-HR?
4037-HR has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 4037-HR easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machine in the annealed or ≤32 HRC Q&T condition with coated carbide, ~120–180 m/min; above 36 HRC expect tool wear and prefer grinding or hard turning with CBN.
Can 4037-HR be welded?
Yes — weldability is rated good (55/100). Weldable with low-hydrogen consumables but the ~0.37 %C requires 200–300 °C preheat, interpass control and post-weld temper/stress relief to avoid HAZ cracking.
What surface finishes work on 4037-HR?
No inherent corrosion resistance — specify zinc, zinc-nickel or chrome plating, black oxide, phosphate-and-oil or paint; bake after plating at ≥190 °C to relieve hydrogen embrittlement above 32 HRC.
Can 4037-HR be formed, bent or molded?
Cold heading and bending are practical only in the annealed/spheroidized state; hot forge 1200 °C down to ~950 °C then normalize before quench and temper.
What is the maximum service temperature of 4037-HR?
4037-HR 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 4037 QT-28-32HRC and 4037-HR?
QT-28-32HRC is the default condition — standard general-purpose condition for machined shafts, studs and high-strength fasteners. HR: cheapest mill condition for parts that will be heat treated after rough machining or forging. Yield strength is 860 MPa in QT-28-32HRC versus 380 MPa in HR.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J429 — Mechanical and Material Requirements for Externally Threaded Fasteners — SAE International (2014)
- ASTM A322 — Standard Specification for Steel Bars, Alloy, Hot-Wrought — ASTM (2020)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4A — Steel Heat Treating Fundamentals and Processes — ASM International (2013)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.