Steel A5 HT 50-52 HRC
Hardness band
AISI/SAE A5 · UNS T30105
HT 50-52 HRC = hardened + tempered 480–540 °C
Maximum-toughness setting for large, heavily shock-loaded tools or where nitriding/EDM follow-up is planned.
Values for the HT 50-52 HRC condition
Other A5 tempers and conditions
A5 is listed in 7 conditions; see the grade overview at A5.
- SR
- ANN
- HT 50-52 HRC
- HT 54-56 HRC
- HT 57-59 HRC
- HT 60-62 HRC
- AQ
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Interim step for large or asymmetric tools to minimise distortion during subsequent air hardening. | 430 | 740 | 23 | 20 HRC | 2.7 % IACS |
ANNDefault Annealed | Standard as-supplied stock condition for machining the tool before hardening. | 435 | 745 | 22 | 225 HB | — |
HT 50-52 HRCThis page Hardened + tempered 480–540 °C | Maximum-toughness setting for large, heavily shock-loaded tools or where nitriding/EDM follow-up is planned. | 1,450 | 1,700 | 6 | 51 HRC | — |
Hardened + tempered 400–425 °C | Tougher setting for heavy-section dies, trim tools and shock-loaded punches. | 1,600 | 1,850 | 4 | 55 HRC | — |
Hardened + tempered 260–315 °C | Balanced wear/toughness setting for general blanking dies, form tools and shear blades. | 1,720 | 1,980 | 2 | 58 HRC | — |
Hardened + tempered 175–205 °C | Maximum wear resistance for blanking and piercing punches and dies in thin, non-abrasive stock. | 1,900 | 2,150 | 1 | 61 HRC | — |
As air-quenched | Intermediate condition only — must be tempered immediately; shown for hardening-response reference. | 1,950 | 2,200 | 1 | 63 HRC | 2.3 % IACS |
What is A5 HT 50-52 HRC?
A5 HT 50-52 HRC is A5 heat treated to HT 50-52 HRC — maximum-toughness setting for large, heavily shock-loaded tools or where nitriding/EDM follow-up is planned. A5 HT 50-52 HRC has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Elongation at break is 6% and the elastic modulus is 203 GPa (29.4 Msi). A5 HT 50-52 HRC has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,400°C (2,552 °F). ANN is the default condition FabDigit quotes; HT 50-52 HRC is available on request or by drawing note.
Advantages
- High strength — 1,450 MPa (210 ksi), better than 97% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 16/100, worse than 98% of steel grades
- Limited ductility — 6%, worse than 97% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
A5 HT 50-52 HRC properties
Typical room-temperature values for A5 HT 50-52 HRC; 10 are specific to this condition. Other listed values are A5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A5 HT 50-52 HRC has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
A5 HT 50-52 HRC has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Elongation at break is 6% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
A5 HT 50-52 HRC is rated for continuous service to 420°C (788 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
A5 HT 50-52 HRC conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of A5 HT 50-52 HRC takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 40%.
Manufacturability6
A5 HT 50-52 HRC's machinability is poor (16/100, worse than 98% of steel grades); weldability poor (20/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A5 HT 50-52 HRC
Is A5 easy to machine?
Machine in the annealed condition with rigid setups, sharp carbide or cobalt HSS and moderate speeds; the high-Mn matrix work-hardens and tends to gum, so avoid dwelling and use positive rake; after hardening only grinding, EDM or hard turning with CBN is practical.
Can A5 be welded?
Weld only for tool repair: preheat/interpass 200–300 °C, matching tool-steel or high-alloy filler, small stringer beads, then temper at 15–25 °C below the last tempering temperature; never weld cold or leave untempered.
Can A5 be formed, bent or molded?
Hot forge 1040–870 °C with slow furnace cooling and immediate spheroidize anneal at ~760–790 °C; cold forming is limited to light coining or straightening of annealed stock.
What surface finishes work on A5?
Takes a good ground and lapped/polished finish at 58–62 HRC; protect with oil, phosphate, black oxide, hard chrome or TiN/TiCN/CrN PVD (deposit below the tempering temperature) since the steel has no inherent corrosion resistance.
A5 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 | 0.95 – 1.05 | 1 |
| MnHigh Mn gives deep air hardening and low austenitizing temperature | 2.5 – 3 | 2.75 |
| Si | ≤ 0.5 | 0.3 |
| Cr | 0.9 – 1.2 | 1 |
| Mo | 0.9 – 1.4 | 1.05 |
| VOptional / residual in some producer practice | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
A5 HT 50-52 HRC — frequently asked
What is A5 HT 50-52 HRC used for?
A5 HT 50-52 HRC is typically used for blanking dies, forming dies and gauges. In short: air-hardening, low distortion; deep hardening cold-work grade; tougher than D-series.
What is the yield strength of A5 HT 50-52 HRC?
A5 HT 50-52 HRC has a typical yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,700 MPa (247 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is A5 HT 50-52 HRC easy to machine?
Not especially — machinability is rated poor (16/100, worse than 98% of steel grades). Machine in the annealed condition with rigid setups, sharp carbide or cobalt HSS and moderate speeds; the high-Mn matrix work-hardens and tends to gum, so avoid dwelling and use positive rake; after hardening only grinding, EDM or hard turning with CBN is practical.
Can A5 HT 50-52 HRC be welded?
Not readily — weldability is rated poor (20/100). Weld only for tool repair: preheat/interpass 200–300 °C, matching tool-steel or high-alloy filler, small stringer beads, then temper at 15–25 °C below the last tempering temperature; never weld cold or leave untempered.
What surface finishes work on A5 HT 50-52 HRC?
Takes a good ground and lapped/polished finish at 58–62 HRC; protect with oil, phosphate, black oxide, hard chrome or TiN/TiCN/CrN PVD (deposit below the tempering temperature) since the steel has no inherent corrosion resistance.
Can A5 HT 50-52 HRC be formed, bent or molded?
Hot forge 1040–870 °C with slow furnace cooling and immediate spheroidize anneal at ~760–790 °C; cold forming is limited to light coining or straightening of annealed stock.
What is the maximum service temperature of A5 HT 50-52 HRC?
A5 HT 50-52 HRC is rated for continuous use to about 420°C (788 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A5-ANN and A5-AQ?
ANN is the default condition — standard as-supplied stock condition for machining the tool before hardening. AQ: intermediate condition only — must be tempered immediately; shown for hardening-response reference. Yield strength is 435 MPa in ANN versus 1,950 MPa in AQ.
Sources
- ASTM A681 — Standard Specification for Tool Steels, Alloy — ASTM International (2015)
- SAE J437/J438 — Tool and Die Steels — SAE International (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- ASM Specialty Handbook: Tool Materials — ASM International (1995)
- Heat Treater's Guide: Practices and Procedures for Irons and Steels — ASM International (1995)
- Air-hardening cold-work tool steel (A-series) data sheets — Crucible / Latrobe / Böhler-Uddeholm (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.