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JIS G3113 Structural Automobile Hot Rolled SAPH400 Steel

What is SAPH400 Steels? SAPH400 steel is a structural Hot Rolled steel in the form of plates, sheets & strips for automobile structural applications. SAPH400 is a material grade and designation defined in JIS G 3113 standard. JIS G 3113 is a Japanese material standard for hot rolled steel plates, sheets, strips for automobile structural usage. The structural quality hot rolled SAPH400 steel is more reliable in its tensile strength than SAPH370 steel. It can be used in automobile applications where more strength is needed & the material does not fail under exceeding loading.  Dimensional Characteristics of SAPH400 Steels: The applicable thickness for this SAPH400 material as defined in the JIS 3113 starts from 2 mm to 14 mm. However the width of SAPH400 material ranges to 950 to 2000 mm.

The Chemical Composition of SAPH400 Steels: JIS G 3113 defines the chemical composition of SAPH400 steels as under:

Carbon (C) is not identified in the standard.

Manganese (Mn) is not identified in the standard.

Maximum percentage of Phosphorous (P) is 0.040 percent.

Maximum percentage of Sulphur (S) is 0.040 percent.

Remaining is iron (Fe) percentage and with few negligible impurities.

Mechanical Properties of SAPH400 Steels: The tensile strength of the SAPH400 Steels is expressed in Newton per millimeters and it must be at-least 400 N/mm2 (MPa). The yield strength is minimum 235 to minimum 255 N/mm2 (MPa) depending on the thickness. The elongation property of SAPH400 steel varies with the ranges of thickness.  The minimum percentage ranges for elongation is 32 to 36 minimum. Only over 6.5 mm thickness requires 24 minimum percentage elongations.

Some other hot rolled commercial quality materials are also used in industrial applications, SPHC steel comparison with this grade of SAPH400 material will show how structural automobile hot rolled steel differs with commercial quality SPHC steel in chemical composition & mechanical properties.


Engineer Ali Alvi is an industrial engineer who has post graduated from the NED University, then completed his Masters in Industrial Engineering from the University of Ontario. He has also served as an engineer in International Steel Ltd as A Cold rolling mill engineer.

  1. James says:

    Hello, I was researching the difference between the SAPH400 and SAPH440. I am told the SAPH400 may not be made in US. Please, help me understand the difference in the 2 grades and wheter you could substitute one for the other. This would be used to stamp a steel flat ribbed gear for automotive OEM application.
    Thank you for the support

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