Hardness and Tensile Strength of Steels: Brinell and Rockwell Scales

Following is an estimate of the relationship between various hardness scales and the tensile strength of standard steels.  It should be considered as a general comparison not applicable to all materials:

Hardness Conversion Table

Brinell Hardness Rockwell Hardness
Tungsten Carbide Ball 3000 KG A Scale 60 kg B Scale 100 kg C Scale 150 kg Tensile Stength (approx.)
86 68
85 68
85 67
767 85 66
757 84 66
745 84 65
733 84 65
722 83 64
712 83 64
710 83 63
698 83 62
684 82 62
682 82 62
670 82 61
656 81 60
653 81 60
647 81 60
638 81 59 329,000
630 81 59 324,000
627 80 59 323,000
601 80 57 309,000
578 79 56 297,000
555 78 55 285,000
534 78 54 274,000
514 77 52 263,000
495 76 51 253,000
477 76 50 243,000
461 75 48 235,000
444 74 47 225,000
429 73 46 217,000
415 73 44 210,000
401 72 43 202,000
388 71 42 195,000
375 71 40 188,000
363 70 39 182,000
352 69 38 176,000
341 69 37 170,000
331 68 36 166,000
321 68 34 160,000
311 67 33 155,000
302 66 32 150,000
293 66 31 145,000
285 65 30 141,000
277 65 29 137,000
269 64 28 133,000
262 64 27 129,000
255 63 25 126,000
248 62 24 122,000
241 62 100 23 118,000
235 61 99 22 115,000
229 61 98 20 111,000
223 97 20
217 96 18 105,000
212 96 17 102,000
207 95 16 100,000
201 94 15 98,000
197 93 95,000
192 92 93,000
187 91 90,000
183 90 89,000
179 89 87,000
174 88 85,000
170 87 83,000
167 86 81,000
163 85 79,000
156 83 76,000
149 81 73,000
143 79 71,000
137 76 67,000
131 74 65,000
126 72 63,000
121 70 60,000
116 68 58,000
111 66 56,000

Machinability of Metals


Machinability is the defined as the ease with which a material can be machined. The American Iron and Steel Institute has determined that AISI 1112 Steel has a machinability of 100%. Other materials are compared below:

Carbon Steels

  • 1015 – 72%
  • 1018 – 78%
  • 1020 – 72%
  • 1022 – 78%
  • 1030 – 70%
  • 1040 – 64%
  • 1042 – 64%
  • 1050 – 54%
  • 1095 – 42%
  • 1117 – 91%
  • 1137 – 72%
  • 1141 – 70%
  • 1141 annealed – 81%
  • 1144 – 76%
  • 1144 annealed – 85%
  • 1144 stress-proof – 83%
  • 1212 – 100%
  • 1213 – 136%
  • 12L14 – 170%
  • 1215 – 136%

Alloy Steels

  • 2355 annealed – 70%
  • 4130 annealed – 72%
  • 4140 annealed – 66%
  • 4142 annealed – 66%
  • 41L42 annealed – 77%
  • 4150 annealed – 60%
  • 4340 annealed – 57%
  • 4620 – 66%
  • 4820 annealed – 49%
  • 52100 annealed – 40%
  • 6150 annealed – 60%
  • 8620 – 66%
  • 86L20 – 77%
  • 9310 annealed – 51%

Stainless Steels and Super Alloys

  • 302 annealed – 45%
  • 303 annealed – 78%
  • 304 annealed – 45%
  • 316 annealed – 45%
  • 321 annealed – 36%
  • 347 annealed – 36%
  • 410 annealed – 54%
  • 416 annealed – 110%
  • 420 annealed – 45%
  • 430 annealed – 54%
  • 431 annealed – 45%
  • 440A – 45%
  • 15-5PH condition A – 48%
  • 17-4PH condition A – 48%
  • A286 aged – 33%
  • Hastelloy X – 19%

Tool Steels

  • A-2 – 42%
  • A-6 – 33%
  • D-2 – 27%
  • D-3 – 27%
  • M-2 – 39%
  • O-1 – 42%
  • O-2 – 42%

Gray Cast Iron

  • ASTM class 20 annealed – 73%
  • ASTM class 25 – 55%
  • ASTM class 30 – 48%
  • ASTM class 35 – 48%
  • ASTM class 40 – 48%
  • ASTM class 45 – 36%
  • ASTM class 50 – 36%

Nodular Ductile Iron

  • 60-40-18 annealed – 61%
  • 65-45-12 annealed – 61%
  • 80-55-06 – 39%

Aluminum / Magnesium Alloys

  • aluminum, cold drawn – 360%
  • aluminum, cast – 450%
  • aluminum, die cast – 76%
  • magnesium, cold drawn – 480%
  • magnesium, cast – 480%

Galvanic Compatibility of Metals – Anodic Index


Galvanic 

Designs sometimes cause dissimilar metals to be in contact within an assembly.  Increased variance of the two metals’ anodic index cause accelerated corrosion of the more anodic metal.  The variance in anodic index can be controlled somewhat through coatings (paint, epoxy, powder coat, etc) and plating (zinc, chrome, etc).

The table below provides a generalize guide for predicting the anodic corrosion two dissimilar metals are prone to.  The service environment also plays a role:

  • For harsh environments: outdoors, high humidity, and salt environments fall into this category. Typically there should be not more than 0.15 V difference in the “Anodic Index”. For example; gold – silver would have a difference of 0.15V being acceptable.
  • For normal environments: storage in warehouses or non-temperature and humidity controlled environments. Typically there should not be more than 0.25 V difference in the “Anodic Index”.
  • For controlled environments: where the temperature and humidity controlled, 0.50 V can be tolerated. Caution should be maintained when deciding for this application as humidity and temperature do vary from regions.

Anodic Index

Metallurgy Index (V)
Gold, solid and plated, Gold-platinum alloy 0.00
Rhodium plated on silver-plated copper 0.05
Silver, solid or plated; monel metal. High nickel-copper alloys 0.15
Nickel, solid or plated, titanium an s alloys, Monel 0.30
Copper, solid or plated; low brasses or bronzes; silver solder; German silvery high copper-nickel alloys; nickel-chromium alloys 0.35
Brass and bronzes 0.40
High brasses and bronzes 0.45
18% chromium type corrosion-resistant steels 0.50
Chromium plated; tin plated; 12% chromium type corrosion-resistant steels 0.60
Tin-plate; tin-lead solder 0.65
Lead, solid or plated; high lead alloys 0.70
Aluminum, wrought alloys of the 2000 Series 0.75
Iron, wrought, gray or malleable, plain carbon and low alloy steels 0.85
Aluminum, wrought alloys other than 2000 Series aluminum, cast alloys of the silicon type 0.90
Aluminum, cast alloys other than silicon type, cadmium, plated and chromate 0.95
Hot-dip-zinc plate; galvanized steel 1.20
Zinc, wrought; zinc-base die-casting alloys; zinc plated 1.25
Magnesium & magnesium-base alloys, cast or wrought 1.75
Beryllium 1.85

Steel Grade Equivalent Table (EN, SAE/AISI, UNS, DIN, BS, UNI, JIS)


The table below compares common grades of materials from various international specifications.  Note that materials compared are the nearest available grade and may have slight variations in actual chemistry.

Comparison of steel grades by chemistry
EN # EN name SAE UNS DIN BS 970 UNI JIS
Carbon steels
1.1141
1.0401
1.0453
C15D
C18D
1018 CK15
C15
C16.8
040A15
080M15
080A15
EN3B
C15
C16
1C15
S15
S15CK
S15C
1.0503
1.1191
1.1193
1.1194
C45 1045 C45
CK45
CF45
CQ45
060A47
080A46
080M46
C45
1C45
C46
C43
S45C
S48C
1.0726
1.0727
35S20
45S20
1140/1146 35S20
45S20
212M40
En8M
1.0715
1.0736
11SMn37 1215 9SMn28
9SMn36
230M07
En1A
CF9SMn28
CF9SMn36
SUM 25
SUM 22
1.0718
1.0737
11SMnPb30
11SMnPb37
12L14 9SMnPb28
9SMnPb36
230M07 Leaded
En1A Leaded
CF9SMnPb29
CF9SMnPb36
SUM 22L
SUM 23L
SUM 24L
Alloy steels
1.7218 4130 25CrMo4
GS-25CrMo4
708A30
CDS110
25CrMo4 (KB)
30CrMo4
SCM 420
SCM 430
SCCrM1
1.7223
1.7225
1.7227
1.3563
42CrMo4 4140/4142 41CrMo4
42CrMo4
42CrMoS4
43CrMo4
708M40
708A42
709M40
En19
En19C
41CrMo4
38CrMo4 (KB)
G40 CrMo4
42CrMo4
SCM 440
SCM 440H
SNB 7
SCM 4M
SCM 4
1.6582
1.6562
34CrNiMo6 4340 34CrNiMo6
40NiCrMo8-4
817M40
En24
35NiCrMo6 (KB)
40NiCrMo7 (KB)
SNCM 447
SNB24-1-5
1.6543
1.6523
20NiCrMo2-2 8620 21NiCrMo22
21NiCrMo2
805A20
805M20
20NiCrMo2 SNCM 200 (H)
Stainless steels
1.4310 X10CrNi18-8 301 S30100
1.4318 X2CrNiN18-7 301LN
1.4305 X8CrNiS18-9 303 S30300 X10CrNiS18-9 202S 21
En58M
X10CrNiS18-09 SUS 303
1.4301 X2CrNi19-11
X2CrNi18-10
304 S30400 X5CrNi18-9
X5CrNi18-10
XCrNi19-9
304S 15
304S 16
304S 18
304S 25
En58E
X5CrNi18-10 SUS 304
SUS 304-CSP
1.4306 X2CrNi19-11 304L S30403 304S 11 SUS304L
1.4311 X2CrNiN18-10 304LN S30453
1.4948 X6CrNi18-11 304H S30409
1.4303 X5CrNi18-12 305 S30500
1.4401
1.4436
X5CrNiMo17-12-2
X5CrNiMo18-14-3
316 S31600 X5CrNiMo17 12 2
X5CrNiMo17 13 3
X5CrNiMo 19 11
X5CrNiMo 18 11
316S 29
316S 31
316S 33
En58J
X5CrNiMo17 12
X5CrNiMo17 13
X8CrNiMo17 13
SUS 316
SUS316TP
1.4404 X2CrNiMo17-12-2 316L S31603 316S 11 SUS316L
1.4406
1.4429
X2CrNiMoN17-12-2
X2CrNiMoN17-13-3
316LN S31653
1.4571 316Ti S31635 X6CrNiMoTi17-12 320S 33
1.4438 X2CrNiMo18-15-4 317L S31703
1.4541 321 S32100 X6CrNiTi18-10 321S 31 SUS321
1.4878 X12CrNiTi18-9 321H S32109
1.4512 X6CrTi12 409 S40900
410 S41000
1.4016 430 S43000 X6Cr17 430S 17 SUS430
440A S44002
1.4112 440B S44003
1.4125 440C S44004
1.4104 440F S44020 X14CrMoS17 SUS430F
1.4539 X1NiCrMoCu25-20-5 904L N08904
1.4547 X1CrNiMoCuN20-18-7 S31254
Tool steels
1.2363 X100CrMoV5 A-2 X100CrMoV51 BA 2 X100CrMoV5-1 KU SKD 12
1.2379 X153CrMoV12 D-2 X153CrMoV12-1 BD 2 X155CrVMo12-1 SKD 11
1.2510 O-1 100MnCrW4 Bo 1 95MnWCr-5 KU

Reference

AISI / SAE STEEL NUMBERING SYSTEM


  • The first two numbers indicate the alloy according the the chart below.
  • The last two numbers indicate the amount of carbon in the alloy, where the digits “10”, for example, represent 0.10% carbon.

Example AISI/SAE 1020

  • the first two digits indicate this is plain carbon steel.
  • the last two digits indicates that the steel contains approximately 0.20% carbon.

Example AISI/SAE 4340

  • the first two digits indicate this is a Nickel-Chromium-Molybdenum alloy steel
  • the last two digits indicate that the steel contains approximately 0.4% carbon
AISI/SAE Steel Numbering System

Carbon steels 10XX Plain carbon, Mn 1.00% max
11XX Resulfurized free machining
12XX Resulfurized/rephosphorized free machining
15XX Plain carbon, Mn 1.00-1.65%
Manganese steel 13XX Mn 1.75%
Nickel steels 23XX Ni 3.50%
25XX Ni 5.00%
Nickel-chromium steels 31XX Ni 1.25%, Cr .65-.80%
32XX Ni 1.75%, Cr 1.07%
33XX Ni 3.50%, Cr 1.50-1.57%
34XX Ni 3.00%, Cr .77%
Molybdenum steels 40XX Mo .20-.25%
44XX Mo .40-.52%
Chromium-molybdenum steels 41XX Cr .50-.95%, Mo .12-.30%
Nickel-chromium-molybdenum steels 43XX Ni 1.82%, Cr .50-.80%, Mo .25%
47XX Ni 1.05%, Cr .45%, Mo .20-.35%
Nickel-molybdenum steels 46XX Ni .85-1.82%, Mo .20-.25%
48XX Ni 3.50%, Mo .25%
Chromium steels 50XX Cr .27-.65%
51XX Cr .80-1.05%
50XXX Cr .50%, C 1.00% min
51XXX Cr 1.02%, C 1.00% min
52XXX Cr 1.45%, C 1.00% min
Chromium-vanadium steels 61XX Cr .60-.95%, V .10-.15%
Tungsten-chromium steels 72XX W 1.75%, Cr .75%
Nickel-chromium-molybdenum steels 81XX Ni .30%, Cr .40%, Mo .12%
86XX Ni .55%, Cr .50%, Mo .20%
87XX Ni .55%, Cr .50%, Mo .25%
88XX Ni .55%, Cr .50%, Mo .35%
Silicon-manganese steels 92XX Si 1.40-2.00%, Mn .65-.85%, Cr 0-.65%
Nickel-chromium-molybdenum steels 93XX Ni 3.25%, Cr 1.20%, Mo .12%
94XX Ni .45%, Cr .40%, Mo .12%
97XX Ni .55%, Cr .20%, Mo .20%
98XX Ni 1.00%, Cr .80%, Mo .25%

Metal Gauge Chart – Steel, Stainless, Aluminum, Tubing


All Dimensions in Inches

Gauge # Sheet Steel Strip & Tubing Aluminum Stainless Steel
6/0
5/0
4/0
3/0
2/0
—-
—-
—-
—-
—-
—-
.500
.454
.425
.380
.5800
.5165
.4600
.4096
.3648
.4687
.4375
.4062
.3750
.3437
0
1
2
3
4
5
—-
—-
—-
.2391
.2242
.2092
.340
.300
.284
.259
.238
.220
.3249
.2893
.2576
.2294
.2043
.1819
.3125
.2812
.2656
.2500
.2344
.2187
6
7
8
9
10
11
.1943
.1793
.1644
.1495
.1345
.1196
.203
.180
.165
.148
.134
.120
.1620
.1443
.1285
.1144
.1019
.0907
.2031
.1875
.1719
.1562
.1406
.1250
12
13
14
15
16
17
.1046
.0897
.0747
.0673
.0598
.0538
.109
.095
.083
.072
.065
.058
.0808
.0720
.0641
.0571
.0508
.0453
.1094
.0937
.0781
.0703
.0625
.0562
18
19
20
21
22
23
.0478
.0418
.0359
.0329
.0299
.0269
.049
.042
.035
.032
.028
.025
.0403
.0359
.0320
.0285
.0253
.0226
.0500
.0437
.0375
.0344
.0312
.0281
24
25
26
27
28
29
.0239
.0209
.0179
.0164
.0149
.0135
.022
.020
.018
.016
.014
.013
.0201
.0179
.0159
.0142
.0126
.0113
.0250
.0219
.0187
.0172
.0156
.0141
30
31
32
33
34
35
36
37
38
.0120
.0105
.0097
.0090
.0082
.0075
.0067
.0064
.0060
.012
.010
.009
.008
.007
.005
.004
—-
—-
.0100
.0089
.0080
.0071
.0063
.0056
.0050
.0045
.0040
.0125
.0109
.0102
.0094
.0086
.0078
.0070
.0066
.0062