Steel 5160 Q&T 205C
Hardness band
AISI/SAE 5160 · UNS G51600 · EN 55Cr3, 1.7176
Maximum hardness/wear resistance for blades and wear parts; low toughness, use only in thin sections.
Values for the Q&T 205C condition
Other 5160 tempers and conditions
5160 is listed in 11 conditions; see the grade overview at 5160.
- Annealed
- Spheroidize Annealed
- Normalized
- Hot Rolled
- Cold Drawn
- Q&T 650C
- Q&T
- Q&T 425C
- Oil Quenched
- Q&T 315C
- Q&T 205C
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault full anneal ~815 °C, slow cool | Softest condition for machining, bending and forming before hardening; most commonly stocked bar/flat condition. | 275 | 725 | 17 | 197 HB | — |
subcritical, spheroidal carbides | Choose for maximum cold formability/upsetting and best tool life when machining before hardening. | 340 | 660 | 22 | 183 HB | 7.8 % IACS |
855 °C, air cool | Uniform fine pearlitic structure; used to refine grain and homogenize forgings before final hardening. | 530 | 957 | 17.5 | 27 HRC | 7.8 % IACS |
as-rolled bar / flat / coil | Lowest-cost mill condition for parts that will be heat treated after machining or forming. | 550 | 900 | 14 | 25 HRC | 7.8 % IACS |
cold-finished annealed bar | Pick for close size tolerance and straight, bright bar for machined parts prior to hardening. | 700 | 860 | 10 | 24 HRC | 7.8 % IACS |
high temper (≈30 HRC) | Softest tempered condition — maximum ductility/toughness where moderate strength is sufficient. | 895 | 1,005 | 20 | 31 HRC | 7.6 % IACS |
Quenched and tempered | General-purpose high-toughness structural condition for shafts, links and heavy-duty machined parts. | 1,160 | 1,310 | 12 | 42 HRC | — |
medium temper (≈50 HRC) | Balanced strength/toughness level often used for heavy springs, torsion bars and impact tools. | 1,640 | 1,790 | 9 | 50 HRC | 7 % IACS |
Oil Quenched (as-quenched, untempered martensite) | Intermediate process condition only — must be tempered promptly; brittle and crack-prone as quenched. | 1,750 | 2,200 | 1 | 63 HRC | 6.6 % IACS |
medium-low temper (≈53–55 HRC) | High strength with slightly improved toughness over a 205 °C temper; typical for knives and cutting edges. | 1,770 | 2,000 | 6 | 54 HRC | 6.8 % IACS |
Q&T 205CThis page oil quenched, low temper (≈58–60 HRC) | Maximum hardness/wear resistance for blades and wear parts; low toughness, use only in thin sections. | 1,790 | 2,220 | 4 | 58 HRC | — |
What is 5160 Q&T 205C?
5160 Q&T 205C is 5160 heat treated to Q&T 205C — maximum hardness/wear resistance for blades and wear parts; low toughness, use only in thin sections. 5160 Q&T 205C has a yield strength of 1,790 MPa (260 ksi) and a tensile strength of 2,220 MPa (322 ksi) — stronger than 99% of steel grades. Elongation at break is 4% and the elastic modulus is 205 GPa (29.7 Msi). 5160 Q&T 205C 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). Annealed is the default condition FabDigit quotes; Q&T 205C is available on request or by drawing note.
Advantages
- High strength — 1,790 MPa (260 ksi), better than 99% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Difficult to machine — 10/100, worse than 99% of steel grades
- Limited ductility — 4%, worse than 98% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
5160 Q&T 205C properties
Typical room-temperature values for 5160 Q&T 205C; 11 are specific to this condition. Other listed values are 5160 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
5160 Q&T 205C 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).
Mechanical13
5160 Q&T 205C has a yield strength of 1,790 MPa (260 ksi) and a tensile strength of 2,220 MPa (322 ksi) — stronger than 99% of steel grades. Elongation at break is 4% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
5160 Q&T 205C is rated for continuous service to 150°C (302 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
5160 Q&T 205C conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 5160 Q&T 205C takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 35%.
Manufacturability8
5160 Q&T 205C's machinability is not recommended (10/100, worse than 99% of steel grades); weldability poor (25/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5160 Q&T 205C
Is 5160 easy to machine?
Machine in the annealed/spheroidized state (~200 HB) with rigid setups and carbide tooling; above ~40 HRC expect grinding or hard-turning with CBN.
Can 5160 be welded?
Poor weldability due to high carbon equivalent — preheat 250–350 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding on finished springs.
Can 5160 be formed, bent or molded?
Hot forge 1150–1200 °C and cool slowly; cold bend only when annealed, then oil quench 830–860 °C and temper 400–540 °C for spring properties (shot peen for fatigue).
What surface finishes work on 5160?
Not anodizable; protect with phosphate + oil, black oxide, paint or zinc/nickel plating (bake to avoid hydrogen embrittlement at high hardness); polishes well when hardened.
5160 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 | 0.56 – 0.64 | 0.6 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.7 – 0.9 | 0.8 |
| Pmax, SAE bar practice | ≤ 0.04 | |
| Smax, SAE bar practice | ≤ 0.04 | |
| Fe | balance |
5160 Q&T 205C — frequently asked
What is 5160 Q&T 205C used for?
5160 Q&T 205C is typically used for leaf springs, suspension components and blades. In short: spring-tempered toughness.
What is the yield strength of 5160 Q&T 205C?
5160 Q&T 205C has a typical yield strength of 1,790 MPa (260 ksi) and a tensile strength of 2,220 MPa (322 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 5160 Q&T 205C easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machine in the annealed/spheroidized state (~200 HB) with rigid setups and carbide tooling; above ~40 HRC expect grinding or hard-turning with CBN.
Can 5160 Q&T 205C be welded?
Not readily — weldability is rated poor (25/100). Poor weldability due to high carbon equivalent — preheat 250–350 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding on finished springs.
What surface finishes work on 5160 Q&T 205C?
Not anodizable; protect with phosphate + oil, black oxide, paint or zinc/nickel plating (bake to avoid hydrogen embrittlement at high hardness); polishes well when hardened.
Can 5160 Q&T 205C be formed, bent or molded?
Hot forge 1150–1200 °C and cool slowly; cold bend only when annealed, then oil quench 830–860 °C and temper 400–540 °C for spring properties (shot peen for fatigue).
What is the maximum service temperature of 5160 Q&T 205C?
5160 Q&T 205C is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 5160 Q&T 205C?
Yes — 5160 Q&T 205C is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J404 / J1249 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A689 — Carbon and Alloy Steel Bars for Springs — ASTM (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- GB/T 1222 — (55CrMnA equivalent) — SAC (2016)
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.