GB/T 17600.2-1998 English PDF (GBT17600.2-1998)

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GB/T 17600.2-1998: Steel. Conversion of elongation values. Part 2: Austenitic steels
GB/T 17600.2-1998
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.10
H 22
eqv ISO 2566-2.1984
Steel - Conversion of elongation values
- Part 2. Austenitic steels
ISSUED ON. DECEMBER 07, 1998
IMPLEMENTED ON. JULY 01, 1999
Issued by. China Quality and Technology Supervision Bureau
Table of Contents
Foreword ... 3
ISO foreword ... 4
1 Scope ... 5
2 References ... 5
3 Definitions ... 6
4 Symbols ... 6
5 Elongation conversions ... 7
6 Use of graphs... 10
Foreword
This Standard is equivalent to the International Standard ISO 2566-2.1984
“Steel - Conversion of elongation values - Part 2. Austenitic steels”.
This Standard is identical to ISO 2566-1.1984 in terms of scope of application,
conversion formula and conversion result.
This Standard has the following differences from the ISO standard.
1. This standard gives the basic formula for elongation conversion compared
with ISO 2566-2. The ISO standard only gives conversion formulas under
two specific conditions between 5.65ඥ𝑆଴ and 4ඥ𝑆଴ gauge lengths AND
the non-proportional gauge length, which can be derived from the basic
formula.
2. The conversion formula given in this Standard contains the calculation
formulas in all the conversion tables in the ISO standard. Therefore, the
21 conversion tables in the ISO standard are reduced to 4.
3. The symbols used in this Standard are consistent with GB/T 228-1987
“Metallic materials - Tensile testing” and GB/T 10623-1989 “Metallic
materials - Terms of mechanical test”, which are slightly different from the
ISO standard.
GB/T 17600 consists of two parts under the general title of “Steel - Conversion
of elongation values”.
GB/T 17600. 1-1998 Part 1. Carbon and low alloy steels
GB/T 17600. 2-1998 Part 2. Austenitic steels
This Standard was proposed by National Metallurgical Industry Bureau.
This Standard shall be under the jurisdiction of National Technical Committee
on Steel of Standardization Administration of China.
Drafting organizations of this Standard. China Metallurgical Information
Standardization Institute, Special Steel Co., Ltd. of Benxi Steel Group
Corporation, Steel Research Institute of Taiyuan Iron and Steel Co., Ltd.
Main drafters of this Standard. Jiang Qingmei, Ye Zhenhua, Luan Yan, Du Juan,
Wang Feng, Cai Shida.
Steel - Conversion of elongation values
- Part 2. Austenitic steels
1 Scope
This Standard specifies a method of converting room temperature elongations
after fracture obtained on various gauge lengths. It includes the conversion
formula and the conversion factor table of the elongation, as well as the graphs
for performing such conversions.
This Standard is applicable to the test piece of austenitic stainless steels in
solution treatment condition within the tensile strength range 450 to 750 MPa,
with an original gauge length not exceed 25ඥ𝑆଴, and a width to thickness ratio
not exceed 20.
This Standard is not applicable to cold rolled steels, quenched and tempered
steels and non-austenitic steels.
In the case of plate test piece under 3 mm thickness, the index n in formula (1)
of this Standard increases with decreasing thickness. The conversion value of
elongation shall be the subject of agreement between the customer and the
supplier.
The conversion method of this Standard is adopted internationally, and the
conversions are reliable within the scope of this Standard. However, because
of the various factors influencing the determination of elongations, whether to
use the conversions of this Standard shall be determined by the relevant
standards or agreements
In cases of dispute or arbitration, the elongation value shall be determined on
the gauge length stated in the relevant standards or agreements.
2 References
The following standards contain provisions which, through reference in this
Standard, constitute provisions of this Standard. At the time of publication, the
editions indicated are valid. All standards are subject to revision. The parties
who are using this Standard shall explore the possibility of using the latest
version of the following standards.
5.5 Conversion from the elongation of a non-proportional gauge length to
the elongation of another non-proportional gauge length for test pieces
of different cross-sectional areas
Convert according to formula (1). It may also convert in two steps using Table
4 or Table 5. Firstly, convert the elongation of the known gauge length to the
elongation of the proportional gauge length, such as 5.65ඥ𝑆଴ or 4ඥ𝑆଴; then
convert it to the elongation of the non-proportional gauge length to be obtained.
Example. The elongation of a 40 mm × 15 mm test piece with 200 mm gauge
length is 24 %, which is to be converted to a 30 mm × 10 mm test piece with
200 mm, 100 mm and 50 mm gauge lengths.
Firstly, according to Table 4, convert to the elongation of 5.65ඥ𝑆଴ gauge length,
that is 24 % × 1/0.957 = 25.1 %;
convert to the elongation of 30 mm × 10 mm, 200 mm gauge length, i.e.
ඥ𝑆଴25.1 % × 0.916 = 23.0 %, which is rounded off to 23 %;
convert to the elongation of 30 mm × 10 mm, 100 mm gauge length, ඥ𝑆଴25.1 %
× 1.000 = 25.1 %, which is rounded off to 25 %;
convert to the elongation of 30 mm × 10 mm, 50 mm gauge length, ඥ𝑆଴25.1 %
× 1.093 = 27.40 %, which is rounded off to 27 %.
The elongation of other proportional gauge lengths may be converted according
to the conversion factors given in Table 2.
6 Use of graphs
6.1 Figures 1 to 5 may be used as an alternative quick method for elongation
conversions.
6.2 Figures 1 and 2 are obtained by taking the logarithm on both sides of the
equation according to formula (5). Figure 1 is used for elongation conversions
between 5.65ඥ𝑆଴ and 50 mm gauge lengths. Figure 2 is for elongation
conversions between 5.65ඥ𝑆଴ and 200 mm gauge lengths.
Example. For 25 mm × 12.5 mm test piece with a cross-sectional area of 312.5
mm2 and a gauge length of 200 mm, the elongation is 25 %. It is to obtain the
elongation of 5.65ඥ𝑆଴ gauge length.
Find 312.5 mm2 on the abscissa and find 25 on the ordinate of Figure 2. The
value corresponding to the oblique line passing through the intersection point
is 27.2 %, which is rounded off to 27 %, that is the elongation of 5.65ඥ𝑆଴ gauge
length to be obtained.
6.3 Figures 3 and 4 are obtained by taking the logarithm on both sides of the
equation according to formula (6). They are used for elongation conversions
between 4ඥ𝑆଴ and 50 mm and between 4ඥ𝑆଴ and 200 mm, respectively, using
the same method as 6.2.
6.4 Figure 5 is obtained by taking the logarithm of the conversion factor λ = (K/
Kτ)0.127 of formula (2), i.e..
It is used to obtain the conversion factor λ of various types of test pieces. It shall
operate as follows.
a) calculate the proportionality coefficients K = L0/ඥ𝑆଴ and Kτ = L0τ/ඥ𝑆଴ఛ for
two test pieces;
b) read the conversion factor λ from Figure 5, that is, find K on the abscissa,
find Kτ on the ordinate, and the value corresponding to the oblique line
passing through the intersection point is the λ value;
c) the elongation obtained is δτ = λ • δ.
Example. For 14 mm × 30 mm plate test piece with a cross-sectional area of
600 mm2 and a L0 = 200 mm gauge length, the measured elongation is 24 %.
It is to be converted to the elongation of 30 mm × 31 mm with a cross-sectional
area of 300 mm2 and a L0τ = 100 mm gauge length.
Firstly, obtain K = 200/√600 = 8.16, K...