Steel - Conversion of elongation values- Part 1: Carbon and low alloy steels
1 Scope
This standard specifies a method of converting room temperature percentage elongations after fracture obtained on various gauge lengths. It includes the conversion formula and conversion factor table of elongation and the graph for such conversion.
This standard is applicable to the carbon steel and low alloy steel with tensile strength range 300~700 MPa and in the hot-rolled, hot-rolled and normalized or annealed conditions, with or without tempering.
This standard is not applicable to cold reduced steels, quenched and tempered steels and austenitic steels
It is also not applicable to they be used where the gauge length exceeds 25 or where the width to thickness ratio of the test piece exceeds 20.
In the case of strip under 4 mm thickness, as the index in the formula given in Formula (1) increases with decreasing thickness, the value to be used must be the subject of agreement between the customer and the supplier.
While, as indicated, the conversions in this standard are considered to be reliable within the stated scope, because of the various factors influencing the determination of percentage elongations, they shall be used for acceptance purposes only by standard or agreement.
In cases of dispute, the elongation shall be determined on the gauge length stated in the relevant standard or agreement.
2 Normative references
The following standards contain provision which, through reference in this standard, constitute provisions of this standard. At time of publication, the editions indicated were valid. All the standards will be modified, however, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.
GB/T 228-1987 Metallic materials-Tensile testing
GB/T 8170-1987 Rules for rounding off of numberical values
3 Definitions
For the purposes of this standard, the following definitions apply.
3.1 Gauge length: any length between two marks used for measurement of elongation of test pieces during test. The gauge length before test is the original gauge length, and the gauge length of test piece after fracture is the gauge length after fracture.
3.2 Proportional gauge length: an original gauge length proportional to the square root of the cross-sectional area of the test piece, which may be indicated as L0=K . For example L0=5.65 , 11.3 and 4d0.
GB/T 17600.1-1998 The following standards are cited：
