Steel C17C +AC (Spheroidize annealed)
Heat-treated state
EN 1.0434
Softest condition, chosen for severe cold heading, deep upsetting and cold extrusion of fasteners before case hardening.
Values for the +AC condition
Other C17C tempers and conditions
C17C is listed in 6 conditions; see the grade overview at C17C.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACThis page Spheroidize annealed | Softest condition, chosen for severe cold heading, deep upsetting and cold extrusion of fasteners before case hardening. | 240 | 400 | 32 | 115 HB | — |
Normalized | Use when a uniform fine ferrite-pearlite structure and consistent core properties are needed before carburizing or welding. | 260 | 420 | 28 | 120 HB | — |
Hot rolled | Cheapest as-rolled wire rod or bar for parts that will be re-annealed, hot formed or carburized after machining. | 270 | 430 | 27 | 126 HB | — |
Spheroidize annealed then cold drawn | Preferred cold-heading wire: soft spheroidized core with a lightly drawn, size-controlled bright surface for multi-station headers. | 380 | 480 | 16 | 140 HB | — |
+CDefault Cold drawn | Standard stocked bar/wire: tight tolerance, bright surface and raised strength for machined pins, shafts and studs. | 450 | 550 | 12 | 160 HB | — |
Carburized, quenched and low-temperature tempered (case hardened) | Final service condition for pins, bushings and light gears needing a wear-resistant case over a tough, low-carbon core. | 480 | 700 | 15 | 60 HRC | — |
What is C17C +AC?
C17C +AC is C17C heat treated to +AC — softest condition, chosen for severe cold heading, deep upsetting and cold extrusion of fasteners before case hardening. C17C +AC has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 96% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi). C17C +AC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F). +C is the default condition FabDigit quotes; +AC is available on request or by drawing note.
Advantages
- Forms and bends easily — 95/100, better than 99% of steel grades
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Readily welded — 95/100, better than 97% of steel grades
- Ductile — tolerates forming and impact — 32%, better than 95% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
C17C +AC properties
Typical room-temperature values for C17C +AC; 15 are specific to this condition. Other listed values are C17C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C17C +AC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).
Mechanical15
C17C +AC has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 96% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
C17C +AC is rated for continuous service to 400°C (752 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
C17C +AC conducts electricity at 11 % IACS, better than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C17C +AC takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
C17C +AC's machinability is fair (40/100, worse than 77% of steel grades); weldability excellent (95/100); formability excellent (95/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C17C +AC
Is C17C easy to machine?
Gummy and prone to built-up edge when annealed — use cold-drawn stock, positive rake, high speed and generous coolant; expect ~70 % of 1212 in the +C condition.
Can C17C be welded?
Excellent weldability by MIG/TIG/MMA/resistance with no preheat below ~25 mm; use ER70S-6 class filler and re-carburize or re-heat-treat afterwards if a case is required.
Can C17C be formed, bent or molded?
Designed for severe cold heading, upsetting and extrusion in the +AC or +AC+C condition; hot forming 850–1150 °C, normalize afterwards for uniform core properties.
What surface finishes work on C17C?
No corrosion resistance of its own — zinc plate, zinc-nickel, phosphate-and-oil, or paint; takes a fine but easily rusting polish, and carburized surfaces should be ground after heat treatment.
C17C 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 |
|---|---|---|
| CEN 10263-3 C17C; AISI 1017 0.15–0.20; GB 15 steel 0.12–0.19 | 0.14 – 0.2 | 0.17 |
| Sioften ≤0.10 for cold-heading (Al-killed) wire | ≤ 0.3 | 0.2 |
| MnAISI 1017 0.30–0.60; EN cold-heading grade toward upper range | 0.5 – 0.9 | 0.7 |
| P≤0.040 in AISI 1017 | ≤ 0.03 | 0.02 |
| S≤0.050 in AISI 1017 | ≤ 0.03 | 0.02 |
| Alaluminium-killed, fine grain | 0.02 – 0.06 | 0.04 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance | — |
C17C +AC — frequently asked
What is C17C +AC used for?
C17C +AC is typically used for small gears, pins, bushings and light-duty shafts. In short: highest weldability carbon steel; severe cold-heading grade; soft tough carburizing core.
What is the yield strength of C17C +AC?
C17C +AC has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 96% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is C17C +AC easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Gummy and prone to built-up edge when annealed — use cold-drawn stock, positive rake, high speed and generous coolant; expect ~70 % of 1212 in the +C condition.
Can C17C +AC be welded?
Yes — weldability is rated excellent (95/100). Excellent weldability by MIG/TIG/MMA/resistance with no preheat below ~25 mm; use ER70S-6 class filler and re-carburize or re-heat-treat afterwards if a case is required.
What surface finishes work on C17C +AC?
No corrosion resistance of its own — zinc plate, zinc-nickel, phosphate-and-oil, or paint; takes a fine but easily rusting polish, and carburized surfaces should be ground after heat treatment.
Can C17C +AC be formed, bent or molded?
Designed for severe cold heading, upsetting and extrusion in the +AC or +AC+C condition; hot forming 850–1150 °C, normalize afterwards for uniform core properties.
What is the maximum service temperature of C17C +AC?
C17C +AC 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.
Sources
- EN 10263-3 Steel rod, bars and wire for cold heading and cold extrusion — Case hardening steels — CEN (2017)
- EN 10084 Case hardening steels — Technical delivery conditions — CEN (2008)
- GB/T 699 (15 steel) — SAC (2015)
- SAE J403 / ASTM A29 carbon steel grade 1017 — SAE / ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
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.