Q/BQB 494-2014 English PDF (QBQB494-2014)
Q/BQB 494-2014 English PDF (QBQB494-2014)
See Chinese contents: Q/BQB 494-2014
Q/BQB 494-2014: Cold Rolled Strip for Welded Pipe
Supply Technical Conditions of Baoshan Iron and Steel Co., Ltd.
Cold-rolled steel strips for welded pipes
Replacing Q/BQB 494-2009
This Technical Conditions specifies the classification and code, dimension, shape, weight, technical requirements, inspection and test, packaging, marking and quality certificate of cold-rolled steel strips for welded pipes.
This Technical Conditions applies to the cold-rolled steel strips for welded pipes produced by Baoshan Iron and Steel Co., Ltd. (hereinafter referred to as steel strips).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 222-2006 Permissible tolerances for chemical composition of steel
GB/T 223 Methods for chemical analysis of iron, steel and alloy
GB/T 228.1-2010 Metallic materials - Tensile testing - Part 1. Method of test at room temperature
GB/T 2523-2008 Measuring method of surface roughness and peak count
for cold-rolled metal sheet (strip)
GB/T 2975-1998 Steel and steel products - Location and preparation of test pieces for mechanical testing
GB/T 4336-2002 Standard test method for spark discharge atomic emission - Spectrometric analysis of carbon and low-alloy steel (routine method) GB/T 5027-2007 Metallic materials - Sheet and strip - Determination of
plastic strain ratio
GB/T 5028-2008 Metallic materials - Sheet and strip - Determination of
tensile strain hardening exponent
GB/T 8170-2008 Rules of rounding off for numerical values and expression and judgement of limiting values
GB/T 20066-2006 Steel and iron - Sampling and preparation of samples for the determination of chemical composition
GB/T 20123-2006 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction
furnace (routine method)
GB/T 20125-2006 Low-alloy steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometric method
GB/T 20126-2006 Unalloyed steel - Determination of low carbon content - Part 2. Infrared absorption method after combustion in an induction furnace (with preheating)
Q/BQB 400 Packaging, marking and inspection documents for cold rolled
Q/BQB 401 Dimension, shape, weight and tolerances for cold rolled steel plates and strips
JIS Z2241.2011 Metallic materials - Tensile testing - Method of test at room temperature
3 Classification and code
3.1 The classification of steel strips according to use shall comply with the requirements of Table 1.
BHG1 Single-layer welded pipe
of packaging, transportation, handling and storage, the supply party shall ensure that the surface of steel plates and steel strips does not rust within 6 months from the date of completion of the manufacture. According to the requirements of the demand party, agreed upon between the supply and
demand parties and specified in the contract, products may also be supplied without oiling. For non-oiled products, the supply party will not bear the corresponding product quality responsibility for defects such as rust, scratches and friction marks during the handling, storage and use.
NOTE. The date of issue in the product inspection document is usually specified as the date of completion of the manufacture of the product.
6.4 Mechanical properties
6.4.1 The supply party shall ensure that the mechanical properties of steel strips comply with the requirements of Table 6 within 6 months from the date of completion of the manufacture.
6.4.2 When steel plates and steel strips are supplied according to the specified parts, the supply and demand parties may agree on a range of mechanical properties that meet the processing needs of the part as the acceptance criteria. At this time, the mechanical properties specified in Table 6 will no longer be used as the basis for delivery and acceptance.
6.4.3 Due to the influence of aging, the mechanical properties of steel plates and steel strips will deteriorate with the prolongation of storage time, such as the increase of yield strength and tensile strength, the decrease of elongation after break, formability deteriorates, tensile strain marks appear, etc. It is recommended that users use it as soon as possible.
not less than
Elongation after break
not less than
BHG1 130 ~ 230 280 38
BHG2 160 ~ 240 275 34
a RP0.2 is used when there is no obvious yield, otherwise ReL is used.
b The specimen is the No. 5 specimen specified in JIS Z2241, and the direction of the specimen is longitudinal.
6.5 Surface quality
6.5.1 There shall be no defects, such as holes, surface cracks and lamination, 30 tons, each steel coil constitutes an inspection batch.
7.6 The inspection item, specimen quantity, sampling method and test method of each batch of steel strips shall comply with the requirements of Table 9. 7.7 The supply party may use different inspection and test methods for
acceptance testing. In the event of a dispute, the test shall be carried out using the inspection and test methods specified in this Technical Conditions and the relevant technical requirements.
method Test method
analysis 1/furnace GB/T 20066
GB/T 223, GB/T 4336, GB/T 20123,
GB/T 20125, GB/T 20126
Tensile test 1/batch
Method B in GB/T 228.1
roughness 1/batch GB/T 2523
7.8 For the tensile and roughness test, if the test result of one item does not meet the technical requirements, then take double the quantity of specimens from the same batch for the re-inspection of the unqualified item. If the re- inspection result (including all the indicators required for the test of this item) is qualified, the whole batch is qualified. For the re-inspection result (including all the indicators required for the test of this item), even if one of the indicators is unqualified, the re-inspection is unqualified. If the re-inspection is unqualified, the single piece of product that has been tested and the test result is unqualified cannot be accepted, but the single piece of product in the batch that has not been tested can be resubmitted one by one for test and acceptance.
8 Packaging, marking and inspection documents
The packaging, marking and inspection documents for steel strips shall comply with the requirements of Q/BQB 400. If the manufacturer has special
requirements on the weight of packaging, they shall be indicated in the contract. 9 Rules of rounding off for numerical values
The rules of rounding off for numerical values shall comply with the
requirements of GB/T 8170.