Steel 27SiMn-HR (Hot rolled)
Supply condition
GB 27SiMn
Cheapest mill condition for stock that will be heat treated after machining or forging.
Values for the HR condition
Other 27SiMn tempers and conditions
27SiMn is listed in 9 conditions; see the grade overview at 27SiMn.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — pick for deep machining, cold sizing or before final quench and temper. | 350 | 620 | 22 | 200 HB | — |
HRThis page Hot rolled | Cheapest mill condition for stock that will be heat treated after machining or forging. | 420 | 750 | 18 | 225 HB | — |
Normalized | Uniform fine-pearlite structure — used to refine forging grain and stabilise machining stock. | 470 | 800 | 17 | 22 HRC | 7 % IACS |
Normalized and tempered | Choose for large sections where water quenching risks cracking but medium strength is enough. | 480 | 760 | 19 | 20 HRC | 7 % IACS |
Cold drawn | Tight tolerance tube/bar with work-hardened strength — the usual precursor for honed hydraulic cylinder tube. | 700 | 900 | 12 | 26 HRC | 6.8 % IACS |
Q&T to 28–32 HRC | Pick when impact toughness and machinability matter more than peak strength (drill-collar bodies, thick cylinders). | 820 | 960 | 16 | 30 HRC | — |
QTDefault Quenched and tempered | The standard supply and design condition — full GB/T 3077 strength with ≥39 J toughness for cylinder tubes and drill collars. | 890 | 1,030 | 15 | 32 HRC | — |
Q&T core + induction hardened surface | For piston rods and journals needing 50+ HRC wear surface over a tough Q&T core; high Si aids hardenability. | 890 | 1,030 | 13 | 52 HRC | 6.6 % IACS |
Q&T to 34–38 HRC | Use where wear and yield strength dominate — downhole tool joints, pins, wear sleeves; toughness drops. | 1,000 | 1,150 | 13 | 36 HRC | — |
What is 27SiMn-HR?
27SiMn-HR is 27SiMn supplied in the HR condition — cheapest mill condition for stock that will be heat treated after machining or forging. 27SiMn-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi). 27SiMn-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). QT is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Low electrical conductivity — 6.6 % IACS, worse than 76% of steel grades
27SiMn-HR properties
Typical room-temperature values for 27SiMn-HR; 10 are specific to this condition. Other listed values are 27SiMn reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
27SiMn-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
27SiMn-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
27SiMn-HR is rated for continuous service to 350°C (662 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
27SiMn-HR conducts electricity at 6.6 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 27SiMn-HR takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
27SiMn-HR's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (40/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 27SiMn-HR
Is 27SiMn easy to machine?
Machine in the annealed or normalized condition (≤217 HB) with carbide tooling; at 30+ HRC after Q&T expect ~50 % of 1212 speeds and abrasive tool wear from the high silicon.
Can 27SiMn be welded?
CE ≈0.6–0.7 — preheat 200–300 °C, use low-hydrogen consumables and temper/stress-relieve at 550–600 °C after welding; avoid welding in the fully hardened state.
Can 27SiMn be formed, bent or molded?
Hot forge 1150–850 °C then normalize; cold forming only in the annealed condition, cold-drawn tube must be stress-relieved before heavy bending.
What surface finishes work on 27SiMn?
No anodizing (ferrous); protect with phosphating plus oil, zinc plating, paint, or hard chrome plating on piston rods; bores are typically skive-roller-burnished or honed to Ra ≤0.4 µm.
27SiMn 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 | 0.24 – 0.32 | 0.28 |
| Si | 1.1 – 1.4 | 1.25 |
| Mn | 1.1 – 1.4 | 1.25 |
| Crresidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
27SiMn-HR — frequently asked
What is 27SiMn-HR used for?
27SiMn-HR is typically used for drill pipe, downhole tools and fasteners. In short: chromium-free drill-pipe steel; honed-tube alloy grade; lower-cost 4140 substitute.
What is the yield strength of 27SiMn-HR?
27SiMn-HR has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 27SiMn-HR easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed or normalized condition (≤217 HB) with carbide tooling; at 30+ HRC after Q&T expect ~50 % of 1212 speeds and abrasive tool wear from the high silicon.
Can 27SiMn-HR be welded?
With care — weldability is rated fair (40/100). CE ≈0.6–0.7 — preheat 200–300 °C, use low-hydrogen consumables and temper/stress-relieve at 550–600 °C after welding; avoid welding in the fully hardened state.
What surface finishes work on 27SiMn-HR?
No anodizing (ferrous); protect with phosphating plus oil, zinc plating, paint, or hard chrome plating on piston rods; bores are typically skive-roller-burnished or honed to Ra ≤0.4 µm.
Can 27SiMn-HR be formed, bent or molded?
Hot forge 1150–850 °C then normalize; cold forming only in the annealed condition, cold-drawn tube must be stress-relieved before heavy bending.
What is the maximum service temperature of 27SiMn-HR?
27SiMn-HR is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 27SiMn-QT and 27SiMn-A?
QT is the default condition — the standard supply and design condition — full GB/T 3077 strength with ≥39 J toughness for cylinder tubes and drill collars. A: softest condition — pick for deep machining, cold sizing or before final quench and temper. Yield strength is 890 MPa in QT versus 350 MPa in A.
Sources
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
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.