Tool Steel Hot Hardness Chart
Hot hardness — Rockwell C hardness measured at elevated temperature — for selected high-speed and die steels. The table shows how hardness falls as testing temperature rises, ranking each grade for red hardness in hot-work and high-speed service.
| 아이시 | Room temperature | 315 °C (600 °F) | 425 °C (800 °F) | 540 °C (1000 °F) | 650 °C (1200 °F) |
|---|---|---|---|---|---|
| High-speed tool steels | |||||
| 엠1 | 65 | 61 | 58 | 54 | 32 |
| 엠2 | 65 | 62 | 59 | 55 | 36 |
| M3, 1등급 | 65 | 63 | 60 | 56 | 36 |
| M3, 2등급 | 65 | 63 | 60 | 56 | 36 |
| 엠4 | 66 | 63 | 60 | 56 | 37 |
| 엠7 | 65 | 61 | 58 | 54 | 35 |
| 엠10 | 65 | 60 | 57 | 52 | 33 |
| 엠30 | 65 | 63 | 58 | 55 | 35 |
| 엠33 | 65 | 64 | 60 | 57 | 40 |
| 엠36 | 65 | 64 | 60 | 57 | 40 |
| M42 | 68 | 66 | 65 | 62 | 44 |
| 엠50 | 64 | 59 | 57 | 52 | — |
| M52 | 64 | 60 | 57 | 53 | — |
| 티1 | 65 | 61 | 57 | 53 | 33 |
| 티4 | 65 | 61 | 59 | 55 | 38 |
| 티5 | 66 | 62 | 60 | 56 | 40 |
| 티15 | 68 | 64 | 61 | 57 | 42 |
| Cold-work die steels | |||||
| A2 | 60 | 52 | 46 | 35 | — |
| A8 | 58 | 55 | 52 | 45 | — |
| 디2 | 60 | 53 | 47 | 38 | — |
| 디4 | 62 | 52 | 46 | 37 | — |
| Hot-work die steels | |||||
| H11 | 54 | 49 | 47 | 42 | 22 |
| H12 | 54 | 49 | 47 | 42 | 22 |
| H13 | 55 | 49 | 47 | 42 | 22 |
| H19 | 54 | 51 | 47 | 42 | 31 |
| H21 | 54 | 52 | 49 | 45 | 29 |
| H23 | 41 | 32 | 30 | 28 | 25 |
| H26 | 58 | 54 | 50 | 46 | 31 |
- (에이) Small-diameter bars tested according to the recommended heat treatment.
테이블 노트
Hot hardness measures hardness at elevated temperature after exposure to that temperature — it is the property behind “red hardness” in high-speed and hot-work tool steels. The 540 °C (1000 °F) and 650 °C (1200 °F) columns rank the grades for hot-work service.
The source table lists A8 at the head of both the cold-work and the hot-work groups; it is shown once here, under cold-work die steels.
Values are comparative hardness test results from the source’s reference 7; small variations between heats and test conditions are normal. Reference data for comparison — verify with the applicable heat-treatment schedule for your part.
관련 참조 페이지
H13 공구강 · H11 공구강 · H10 공구강 · H21 공구강 · 고온 작업용 공구강 · 공구강 경화 및 템퍼링 차트 · Tool steel heat treatment guide · 공구강 특성표 · Tool steel composition chart · How to select tool steels
Source: ASM Handbook, Volume 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys, Table 14 “Hot hardness of selected high-speed tool steels and die steels” (10th ed.). Reference data for comparison — verify the applicable heat treatment before service.