Steel S50C · supply condition
Steel S50C-HR
Properties of the HR condition, compared with the other S50C tempers.
Cheapest stock form for weld fabrications and parts that will be machined then heat treated.
What is S50C-HR?
S50C-HR is S50C supplied in the HR condition — cheapest stock form for weld fabrications and parts that will be machined then heat treated. S50C-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 67% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi). S50C-HR 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). Normalized is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 82% of steel grades
Limitations
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 87% of steel grades
S50C-HR properties
Typical room-temperature values for S50C-HR — 11 properties are specific to this condition; the rest are grade-level values shared by every S50C temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
S50C-HR 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
S50C-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 67% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
S50C-HR is rated for continuous service to 350°C (662 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
S50C-HR conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S50C-HR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
S50C-HR's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (35/100); formability poor (32/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other S50C tempers and conditions
S50C is also supplied in 8 other conditions. The full side-by-side table is on the S50C overview.
- NormalizedDefaultDefault stocked condition: uniform fine pearlitic structure, balanced strength and machinability for general shafting and mold plate.427 MPa yield · 217 HB
- Q&T 40-45 HRCMaximum through-hardness practical for S50C in small sections where wear resistance dominates over toughness.1,050 MPa yield · 43 HRC
- Q&T 34-38 HRCHigher-strength Q&T level for wear-loaded pins, cams and small shafts where impact demand is moderate.850 MPa yield · 36 HRC
- Q&T 28-32 HRCGeneral-purpose quench-and-temper level for shafts and gear blanks needing toughness with moderate strength.700 MPa yield · 30 HRC
- CDChoose for close-tolerance, bright bar used as-supplied for shafts, pins and studs with higher yield strength.580 MPa yield · 197 HB
- IH 52-58 HRCUse for shaft journals, guide rails and sprocket teeth needing a hard wear surface over a tough normalized core.430 MPa yield · 55 HRC
- PH 190-220HBStandard S50C mold-base plate condition: stress-relieved, machined flat, used directly without further heat treatment.420 MPa yield · 205 HB
- HRCheapest stock form for weld fabrications and parts that will be machined then heat treated.380 MPa yield · 197 HB
- AnnealedPick when maximum machinability, cold formability or easiest drilling is needed before hardening.365 MPa yield · 187 HB
Working with S50C-HR
Is S50C easy to machine?
Machines predictably at ~50% of 1212; best in annealed or normalized state with carbide tooling, 120–200 m/min turning, ample coolant to avoid built-up edge.
Can S50C be welded?
CE ≈ 0.6 — preheat 200–300 °C, use low-hydrogen E7018/ER70S electrodes and post-weld stress relief or temper to avoid HAZ cracking.
Can S50C be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling; cold bending is limited — use generous radii (≥3t) in the annealed condition only.
What surface finishes work on S50C?
No corrosion resistance bare — protect with black oxide, phosphate, zinc/hard-chrome plating, nitriding or paint; polishes to a fair mold-plate finish but carbide inclusions limit mirror work.
S50C 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 |
|---|---|---|
| CJIS G4051 | 0.47 – 0.53 | 0.5 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Curesidual, max | ≤ 0.3 | 0.1 |
| Niresidual, max | ≤ 0.2 | 0.05 |
| Crresidual; Ni+Cr ≤ 0.35 | ≤ 0.2 | 0.05 |
| Fe | balance | — |
S50C-HR — frequently asked
What is S50C-HR used for?
S50C-HR is typically used for crankshafts, shafts and industrial bolts. In short: workhorse Japanese carbon bar.
What is the yield strength of S50C-HR?
S50C-HR has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 67% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is S50C-HR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machines predictably at ~50% of 1212; best in annealed or normalized state with carbide tooling, 120–200 m/min turning, ample coolant to avoid built-up edge.
Can S50C-HR be welded?
With care — weldability is rated fair (35/100). CE ≈ 0.6 — preheat 200–300 °C, use low-hydrogen E7018/ER70S electrodes and post-weld stress relief or temper to avoid HAZ cracking.
What surface finishes work on S50C-HR?
No corrosion resistance bare — protect with black oxide, phosphate, zinc/hard-chrome plating, nitriding or paint; polishes to a fair mold-plate finish but carbide inclusions limit mirror work.
Can S50C-HR be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling; cold bending is limited — use generous radii (≥3t) in the annealed condition only.
What is the maximum service temperature of S50C-HR?
S50C-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 S50C Normalized and S50C-CD?
Normalized is the default condition — default stocked condition: uniform fine pearlitic structure, balanced strength and machinability for general shafting and mold plate. CD: choose for close-tolerance, bright bar used as-supplied for shafts, pins and studs with higher yield strength. Yield strength is 427 MPa in Normalized versus 580 MPa in CD.
Can FabDigit make parts in S50C-HR?
Yes — S50C-HR is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 4051 — Carbon steels for machine structural use — JSA (2016)
- GB/T 699 — Quality carbon structural steels (50 ) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels (AISI 1050) — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- ASTM A29/A29M — Steel bars, carbon and alloy, hot-wrought — ASTM (2020)
- Mold base plate (S50C) product data — LKM / FUTABA mold base catalogs (2022)
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.