SAE J431 automotive gray iron casting, iron grades, hardness, reference grades and chemical composition.
Iron Grades—Iron grades and their t/h lower limit requirements are shown in Table 1.
TABLE 1—IRON GRADES |
Grade |
Test Bar t/h Ratio Lower Limit (1)
MPa/MPa (2) |
Test Bar t/h Ratio Lower Limit (1)
psi/HB (3)(4) |
G7 |
0.070 |
100 |
G9 |
0.090 |
128 |
G10 |
0.100 |
142 |
G11 |
0.110 |
156 |
G12 |
0.120 |
171 |
G13 |
0.130 |
185 |
1. |
Statistically defined |
2. |
Both tensile and hardness in MPA units |
3. |
For reference only. The MPa/MPa SI metric values are primary. |
4. |
Units of HB are kgf per mm2 . |
Hardness Grades—Hardness grades and their required lower hardness limits are shown in Table 2.
TABLE 2—HARDNESS GRADES |
|
Casting Hardness Lower Limit(1) |
Casting Hardness Lower Limit(1) |
Grade |
MPa (2) |
HB(3) |
H10 |
1000 |
102 |
H11 |
1100 |
112 |
H12 |
1200 |
122 |
H13 |
1300 |
133 |
H14 |
1400 |
143 |
H15 |
1500 |
153 |
H16 |
1600 |
163 |
H17 |
1700 |
173 |
H18 |
1800 |
184 |
H19 |
1900 |
194 |
H20 |
2000 |
204 |
H21 |
2100 |
214 |
H22 |
2200 |
224 |
H23 |
2300 |
235 |
H24 |
2400 |
245 |
1. |
Statistically Defined. |
2. |
Hardness in MPa = HB multiplied by 9.80665. |
3. |
Units of HB are kgf per mm2 . |
Casting Grades—Combination of iron grade, hardness grade, and special requirement designation, if any, defines casting grade. A partial list of casting grades in common production and use, identified as reference grades and considered standard, is given in Table 4 with current and previous SAE designations. Other combinations of iron grade and hardness grade which are established in production and use or become so in the course of application development, or in accordance with 3.5 and 5.5.3, are also considered standard.
TABLE 4—REFERENCE GRADES (1) |
SAE Casting Grade |
Previous SAE Designation (2) |
G9H12 |
G1800 |
G9H17 |
G2500 |
G10H18 |
G3000 |
G11H18 |
G3000 |
G11H20 |
G3500 |
G12H21 |
G4000 |
G13H19 |
G4000 |
G7H16 c |
G1800 h(3) |
G9H17 a |
G2500 a |
G10H21 c |
G3500 c |
G11H20 b |
G3500 b |
G11H24 d |
G4000 d |
1. |
Established in production and use and having near equivalents with previous SAE designations. |
2. |
Equivalency based on tensile strength in 30 mm diameter test bars. See Table A4. |
3. |
The h suffix was previously used to designate both t/h and carbon require-ments for this grade. |
Chemical Composition
Typical base composition ranges generally employed for the iron grades are shown in Table A1. The base composition does not include alloys such as Cu, Cr, Mo, Ni, or others which may be added for hardness or t/h control, or to meet mandatory composition limits of special irons given in Table 3 of the main body of this document.
TABLE A1—TYPICAL BASE COMPOSITIONS |
Iron |
Previous |
|
|
|
Sulfur |
Phosphorus |
C. E.(1) |
Grade |
Designation |
Carbon |
Silicon |
Manganese |
Max. |
max |
(Approx.) |
G7 |
G1800h |
3.50 - 3.70 |
2.30 - 2.80 |
0.60 - 0.90 |
0.14 |
0.25 |
4.35 - 4.55 |
G9 |
G2500 |
3.40 - 3.65 |
2.10 - 2.50 |
0.60 - 0.90 |
0.12 |
0.25 |
4.15 - 4.40 |
G10 |
G3000 |
3.35 - 3.60 |
1.90 - 2.30 |
0.60 - 0.90 |
0.12 |
0.20 |
4.05 - 4.30 |
G11 |
G3000 |
3.30 - 3.55 |
1.90 - 2.20 |
0.60 - 0.90 |
0.12 |
0.10 |
4.00 - 4.25 |
G12 |
G3500 |
3.25 - 3.50 |
1.90 - 2.20 |
0.60 - 0.90 |
0.12 |
0.10 |
3.95 - 4.20 |
G13 |
G4000 |
3.15 - 3.40 |
1.80 - 2.10 |
0.70 - 1.00 |
0.12 |
0.08 |
3.80 - 4.05 |
1. |
C. E. (Carbon Equivalent) = %C + (1/3) %Si. |
For automotive ductile iron grade, please refer to SAE J434.
For comparison with the ASTM A48 grades, please refer to our Comparison Table for Gray Iron Casting Grades.
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