Steel 27SiMn
GB 27SiMn
27SiMn is a chromium-free silicon–manganese low-alloy structural steel, stocked hot-rolled, annealed, normalised, normalised-and-tempered, cold-drawn, honed and quenched-and-tempered to 28–32 or 34–38 HRC.
Reference datasheet — 27SiMn 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
27SiMn tempers and conditions
27SiMn is supplied in 9 conditions, soft to hard. QT is the default FabDigit quotes; the values on this page are for it.
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 | — |
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 | — |
Supply forms, finishes and certifications
Ways 27SiMn is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
HONED | Honed tube | Surface finish |
What is 27SiMn?
27SiMn is a chromium-free silicon–manganese low-alloy structural steel, stocked hot-rolled, annealed, normalised, normalised-and-tempered, cold-drawn, honed and quenched-and-tempered to 28–32 or 34–38 HRC. In the default Q&T condition it gives 890 MPa yield, 1030 MPa tensile, 15 % elongation and about 310 HB (32 HRC) with service to 350 °C, which is why it is used for drill pipe, downhole tooling and honed cylinder tube. Weldability (35/100) and cold formability (25/100) are limited and it offers no corrosion resistance; 4140/42CrMo is the usual alternative when larger hardened sections or higher tempering resistance are needed. 27SiMn 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). 27SiMn has a yield strength of 890 MPa (129 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
What is 27SiMn used for?
- drill pipe
- downhole tools
- fasteners
Advantages
- High strength — 890 MPa (129 ksi), better than 90% of steel grades
- 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 properties
Typical room-temperature values for 27SiMn-QT; bars are the position among steel grades.
Physical3
27SiMn 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 has a yield strength of 890 MPa (129 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
27SiMn 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 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 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's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (35/100); formability poor (25/100).
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. 27SiMn is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 27SiMn
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.
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 |
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.
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
How much does 27SiMn cost?
27SiMn 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.
27SiMn — frequently asked
What is 27SiMn used for?
27SiMn 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?
27SiMn has a typical yield strength of 890 MPa (129 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 27SiMn easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% 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 be welded?
With care — weldability is rated fair (35/100). 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?
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 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?
27SiMn 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.
How much does 27SiMn cost?
27SiMn 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
- 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; 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.