Steel 35# · heat-treated state
Steel 35#-IND
Properties of the IND condition, compared with the other 35# tempers.
Use induction or flame hardening over a quenched-and-tempered core to obtain a 45–55 HRC wear layer on journals, guide faces and pin bores; machining and welding after hardening are impractical.
What is 35#-IND?
35#-IND is 35# heat treated to IND — use induction or flame hardening over a quenched-and-tempered core to obtain a 45–55 HRC wear layer on journals, guide faces and pin bores; machining and welding after hardening are impractical. 35#-IND has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 58% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi). 35#-IND 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). HR is the default condition FabDigit quotes; IND is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- 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
- Difficult to machine — 20/100, worse than 97% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
35#-IND properties
Typical room-temperature values for 35#-IND — 9 properties are specific to this condition; the rest are grade-level values shared by every 35# temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
35#-IND 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).
Mechanical15
35#-IND has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 58% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
35#-IND is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
35#-IND conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 35#-IND takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
35#-IND's machinability is poor (20/100, worse than 97% of steel grades); weldability poor (20/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 35# tempers and conditions
35# is also supplied in 6 other conditions. The full side-by-side table is on the 35# overview.
- HRDefaultTake as-rolled bar or plate as the standard stock for machining, forging blanks or low-to-medium load structural parts at 330 MPa yield and 160 HB.330 MPa yield · 160 HB
- QT-28-32HRCChoose the ~480–540 °C medium temper at 28–32 HRC for small-section shafts, pins and gear blanks needing wear resistance and higher fatigue strength; control quench cracking and accept lower machinability.760 MPa yield · 30 HRC
- CDUse cold drawn bar for tight dimensional accuracy, good surface finish and raised strength in no-machining shafts, pins and screw-machine parts; ductility and residual stress are the limits.520 MPa yield · 190 HB
- QTPick the general-purpose water quench from 850 °C with 550–650 °C temper for balanced strength and toughness in medium-load shafts, connecting rods and flange bolts; sections over ~40 mm will not harden through.470 MPa yield · 18 HRC
- INDUse induction or flame hardening over a quenched-and-tempered core to obtain a 45–55 HRC wear layer on journals, guide faces and pin bores; machining and welding after hardening are impractical.470 MPa yield · 50 HRC
- NChoose normalizing at 850–880 °C with air cooling to refine grain and remove forging or hot-rolling banding; this is the GB/T 699 property sampling state and the usual delivery state for welded structures.345 MPa yield · 170 HB
- APick the fully annealed state (~860 °C, furnace cooled) for the lowest hardness and most uniform structure — best suited to heavy cutting, cold forming or softening before further heat treatment.300 MPa yield · 150 HB
Working with 35#-IND
Is 35# easy to machine?
Machinability is best in the normalized or quenched-and-tempered condition, at 60–70 % of AISI 1212; annealed material tends to smear and burr. Work in the 170–210 HB range with generous coolant.
Can 35# be welded?
At C ≈ 0.36 % weldability is restricted: preheat heavy sections to 100–200 °C, use low-hydrogen electrodes or ER70S-6 wire, and stress relieve at 600–650 °C after welding to prevent cold cracking.
Can 35# be formed, bent or molded?
Hot forge at 1150–850 °C and normalize after forging. Cold bend radii should be at least 2t, and cold-drawn stock is best stress-relief annealed before bending.
What surface finishes work on 35#?
Not anodizable. Use black oxide, phosphating, zinc or hard chrome plating, or paint; oil machined parts before shipment to prevent rust.
35# 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 |
|---|---|---|
| CGB/T 699 35 | 0.32 – 0.4 | 0.36 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Crresidual element | ≤ 0.25 | 0.1 |
| Niresidual element | ≤ 0.3 | 0.1 |
| Curesidual element | ≤ 0.25 | 0.1 |
| Fe | balance | — |
35#-IND — frequently asked
What is 35#-IND used for?
35#-IND is typically used for shafts, industrial bolts and crankshafts. In short: medium-carbon Chinese plate.
What is the yield strength of 35#-IND?
35#-IND has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 58% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 35#-IND easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machinability is best in the normalized or quenched-and-tempered condition, at 60–70 % of AISI 1212; annealed material tends to smear and burr. Work in the 170–210 HB range with generous coolant.
Can 35#-IND be welded?
Not readily — weldability is rated poor (20/100). At C ≈ 0.36 % weldability is restricted: preheat heavy sections to 100–200 °C, use low-hydrogen electrodes or ER70S-6 wire, and stress relieve at 600–650 °C after welding to prevent cold cracking.
What surface finishes work on 35#-IND?
Not anodizable. Use black oxide, phosphating, zinc or hard chrome plating, or paint; oil machined parts before shipment to prevent rust.
Can 35#-IND be formed, bent or molded?
Hot forge at 1150–850 °C and normalize after forging. Cold bend radii should be at least 2t, and cold-drawn stock is best stress-relief annealed before bending.
What is the maximum service temperature of 35#-IND?
35#-IND 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 35#-HR and 35#-CD?
HR is the default condition — take as-rolled bar or plate as the standard stock for machining, forging blanks or low-to-medium load structural parts at 330 MPa yield and 160 HB. CD: use cold drawn bar for tight dimensional accuracy, good surface finish and raised strength in no-machining shafts, pins and screw-machine parts; ductility and residual stress are the limits. Yield strength is 330 MPa in HR versus 520 MPa in CD.
Can FabDigit make parts in 35#-IND?
Yes — 35#-IND 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
- ASM Handbook Vol.1: Properties and Selection: Irons, Steels (1035/1035H) — ASM International (1990)
- Machinery's Handbook, 31st ed. (machinability ratings) — 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.