Q/BQB 301-2018 English PDF (QBQB301-2018)

This Standard specifies the dimension, shape, weight and tolerance of continuously hot-rolled steel sheet and strip. This Standard is applicable to the continuously hot-rolled steel strip produced by Baoshan Iron and Steel Co., Ltd.; as well as the steel sheet horizontally cut from the steel strip and the longitudinally cut steel strip, hereinafter referred to as steel sheet and strip.

Q/BQB 301-2018
ENTERPRISE STANDARD OF
BAOSHAN IRON AND STEEL CO., LTD
Replacing Q/BQB 301-2014
Dimension, Shape, Weight and Tolerances for
Continuously Hot-Rolled Steel Sheet and Strip
ISSUED ON: JANUARY 15, 2018
IMPLEMENTED ON: APRIL 10, 2018
Issued by: Baoshan Iron and Steel Co., Ltd.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Classification and Code ... 5
4 Dimension ... 6
5 Dimension Tolerance ... 7
6 Appearance ... 10
7 Measurement of Dimension and Appearance ... 13
8 Weight ... 14
9 Numerical Rounding-Off Rules ... 14
Appendix A (Normative) Weight Calculation Method by Taking Theoretical
Weight ... 16
Foreword
This Standard was drafted as per the rules specified in GB/T 1.1-2009 Directives for Standardization – Part 1: Structure and Drafting of Standards.
This Standard was formulated by reference of GB/T 709-2006, EN 10051:2010 and ISO 16160:2012, and combined with the actual situation of the Baoshan Iron and Steel Co., Ltd.
This Standard replaced Q/BQB 301-2014.
Compared with Q/BQB 301-2014, this Standard has the major changes as follows: --- Add the classification, code and corresponding provisions of advanced precision of thickness of PT.C, higher width precision without edge trimming of PW.B, and the higher unevenness precision of steel sheet of PF.B;
--- Add product types and nominal size ranges of hot-rolled heat-treated steel sheets and hot-rolled flat strips;
--- Extend the maximum width of steel strip in Table 1 to 2100mm; and the maximum nominal thickness of the pickled surface to 8.0mm;
--- Add provisions for the total length of the tongue and the fish tail of the steel strips without cutting the head and tail;
--- Increase the thickness tolerance to 360MPa in shifts according to the specified minimum yield strength of 345MPa;
--- Add the provisions of the asymmetric thickness tolerance that can be specified; --- Tighten the ordinary accuracy of the unevenness of the steel sheet with a specified minimum yield strength greater than 300MPa and thickness no greater than 2mm;
--- Add the provisions and measurement methods of the unevenness tolerance of the hot-rolled flat steel strips;
--- Add the provisions of the unevenness of the steel strips that are not flattened; --- Tighten the tower-shaped provisions of the finished non-trimming hot-rolled steel strips;
--- Tighten the provisions of out-of-squareness when using diagonal measurement; and add the arbitration method in case of the disputes.
Dimension, Shape, Weight and Tolerances for
Continuously Hot-Rolled Steel Sheet and Strip
1 Scope
This Standard specifies the dimension, shape, weight and tolerance of continuously hot-rolled steel sheet and strip.
This Standard is applicable to the continuously hot-rolled steel strip produced by Baoshan Iron and Steel Co., Ltd.; as well as the steel sheet horizontally cut from the steel strip and the longitudinally cut steel strip, hereinafter referred to as steel sheet and strip.
2 Normative References
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.
GB/T 8170-2008 Rules of Rounding off for Numerical Values and Expression and Judgement of Limiting Values
3 Classification and Code
3.1 It can be divided as follows according to the edge state:
Trimming EC
Non-trimming EM
3.2 It can be divided as follows according to the thickness precision:
Ordinary thickness precision PT.A
Higher thickness precision PT.B
Advanced thickness precision PT.C
3.3 For the non-trimming steel sheet and strip, it can be divided as follows 1000mm in the longitudinal direction of the area no less than 40mm from the longitudinal edge of the steel strip to measure the maximum distance between the upper surface of the steel strip and the ruler.
7.4 Sickle curvature
The maximum distance BETWEEN the concave side of the steel sheet and strip AND the straight line connecting the two ends of the measurement part, as shown in Figure 2. For the steel sheet with length L < 5000mm, the measurement length of the steel sheet is the actual length. For the steel sheet with length L ≥ 5000mm, the measurement length of the steel sheet is any 5000mm.
7.5 Out-of-squareness (slanting)
The vertical projection of the horizontal edge of the steel sheet on the longitudinal edge (as shown in Figure 3); or one-half of the difference between the diagonals of the steel sheet.
8 Weight
8.1 The steel sheet is delivered according to the theoretical or actual weight; while the steel strip shall be delivered according to the actual weight.
8.2 When the steel sheet is delivered by the theoretical weight, the thickness used in the theoretical weight calculation shall be the average between the allowed maximum and minimum thickness; while the width and length shall take the nominal dimensions. Unless otherwise is specified in the product standard, the density shall be 7.85g/cm3. The theoretical weight calculation method is shown in Appendix A (Normative). 8.3 The weight of different types of products shall meet the provisions of Table 14. 9 Numerical Rounding-Off Rules
The numerical judgment is based on rounding-off comparison method. The numerical rounding-off shall conform to the provisions of GB/T 8170.