Material Hardness Values

A.Material Hardness Values
Hardness
Value HRC Hardness
value HRB
Hardness
Value
Vickers
Hardness
Value
Brinnell
N/mm² Symbols DIN
-20 67 114 114 400 C15
-9 74 131 131 460 C10
1 83 154 156 560 C40 stainless 303
10 90 183 182 635
15 93 199 200 680 C55 42CrMo4 32CrMo12
20 97 221 224 760 34CrNiMo6 14NiCr14
25 101 250 249 850 34CrNiMo6 pretreated
30 105 278 276 955
35 109 320 323 1110
40 112 385 370 1270
45 115 460 427 1453 C40
hardened
50 118 535 497 1670 34CrNiMo6
hardened 32NiCrMo45
hardened 42CrMo4 hardened
55    639 545 1870 C35 hardened
57    694 576 1940
60    746 601 2110 14NiCr14
hardened C10
hardened
63    867 652 2220 32CrMo12
nitrited
65    940 682 2300
67    1060 725 2400
70    1170 760 2640

B. Material Hardness ( Heat Treatment )

The following table shows the different processes used in the heat treatment of gears
Material	Carburizing	Hardening temperature	Quenching method	Hardness level obtained	Tempering
Quenched
C40		830/860°C	Hold at 210 to 230°C in an oil bath for 1h/25 mm	40-45 HRc	Hold at 650°C + Cool for one hour in an oven or in the open air
C55		810/840°C	Hold at 210 to 230°C in an oil bath for 1h/25 mm	40-45 HRc	Hold at 650°C + cool for one hour in an oven or in the open air
42CrMo4		860/890°C	Hold at 210 to 230°C in an oil bath for 1h/25 mm	40-45 HRc	Hold at 690°C + cool for one hour in an oven or in the open air
34CrNiMo6		820/850°C	Hold at 180à200°C in an oil bath for 1h/25 mm	40-45 HRc	Hold at 650°C + cool for one hour in an oven or in the open air
Cementation
C10<Ø100	Hold at 900 to 930°C for 1h cementation depth 0,2mm	770/790°C	Hold at 150 to 200°C in an oil bath 1h/25 mm	55-60 HRc	Hold at 650°C + cool for one hour in an oven or in the open air
C10>Ø100	Hold at 900-930°C for 1h cementation depth 0,2mm	900/930°C	Hold at 150 to 200°C in an oil bath 1h/25 mm	57-62 HRc	Hold at 650°C + cool for one hour in an oven or in the open air
12NiCr14	Hold at 900-930°C for 1h cementation depth 0,2mm	820/840°C	Hold at 150 to 200°C in an oil bath 1h/25 mm	57-62 HRc	Hold at 650°C + cool for one hour in an oven or in the open air
*Do not stock or use at temperatures between 250 and 450°C All values are approximate

Hardness Value HRC	Hardness value HRB	Hardness Value Vickers	Hardness Value Brinnell	N/mm²	Symbols DIN
-20	67	114	114	400	C15
-9	74	131	131	460	C10
1	83	154	156	560	C40	stainless 303
10	90	183	182	635
15	93	199	200	680	C55	42CrMo4	32CrMo12
20	97	221	224	760	34CrNiMo6 14NiCr14
25	101	250	249	850	34CrNiMo6 pretreated
30	105	278	276	955
35	109	320	323	1110
40	112	385	370	1270
45	115	460	427	1453	C40 hardened
50	118	535	497	1670	34CrNiMo6 hardened	32NiCrMo45 hardened	42CrMo4 hardened
55		639	545	1870	C35 hardened
57		694	576	1940
60		746	601	2110	14NiCr14 hardened	C10 hardened
63		867	652	2220	32CrMo12 nitrited
65		940	682	2300
67		1060	725	2400
70		1170	760	2640