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Q/BQB 420-2014 English PDF (QBQB420-2014)

Q/BQB 420-2014 English PDF (QBQB420-2014)

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Q/BQB 420-2014: Hot dip galvanized / zinc-iron alloy coated steel sheet and strip

This Technical Conditions specifies the terms and definitions, classification and code, dimension, shape, weight, technical requirements, inspection and test, packaging, marking and inspection documents of hot-dip zinc/zinc-iron alloy coated steel plates and steel strips. This Technical Conditions applies to steel plates and steel strips with a thickness of 0.30 mm ~ 3.0 mm produced by Baoshan Iron and Steel Co., Ltd., which are mainly used for the production of inner and outer covering parts and structural parts of automobiles, construction and home appliances.
Q/BQB 420-2014
Supply Technical Conditions of Baoshan Iron and Steel Co., Ltd.
Hot-dip zinc/zinc-iron alloy coated steel plates and steel strips
Replacing Q/BQB 420-2009
1 Scope
This Technical Conditions specifies the terms and definitions, classification and code, dimension, shape, weight, technical requirements, inspection and test, packaging, marking and inspection documents of hot-dip zinc/zinc-iron alloy coated steel plates and steel strips (hereinafter referred to as steel plates and steel strips).
This Technical Conditions applies to steel plates and steel strips with a thickness of 0.30 mm ~ 3.0 mm produced by Baoshan Iron and Steel Co., Ltd., which are mainly used for the production of inner and outer covering parts and structural parts of automobiles, construction and home appliances.
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
products
GB/T 228.1-2010 Metallic materials - Tensile testing - Part 1. Method of test at room temperature
GB/T 1839-2008 Test method for gravimetric determination of the mass per unit area of galvanized coatings on steel products
GB/T 2975-1998 Steel and steel products - Location and preparation of test 3.8 transformation induced plasticity steels (TR)
The microstructure of the steel is ferrite, bainite and retained austenite, wherein the retained austenite content is not less than 5 %. During the forming process, the retained austenite can be transformed into martensite structure, so that it has relatively high work hardening rate, uniform elongation and tensile strength. It has a higher elongation than a dual phase steel of the same tensile strength. 3.9 complex phase steels (CP)
The microstructure of the steel is mainly ferrite and/or bainite. On the ferrite and/or bainite matrix, a small amount of martensite, retained austenite and pearlite structure are usually distributed. The effect of refining crystal grains or precipitation strengthening is formed by adding microalloying element Ti or Nb. This steel has a very high tensile strength. The yield strength is significantly higher than that of the duplex steel of the same tensile strength. This steel has high energy absorption capacity and high residual strain capability.
3.10 quenching and partitioning steel (QP)
The steel is a kind of high-formability ultra-high-strength steel produced by quenching-partitioning process. The microstructure of the steel is composed of multiphase composites such as martensite + ferrite + retained austenite. Utilizing the ultra-high strength of martensite and the transformation induced plasticity (TRIP) effect of retained austenite, it is possible to obtain better formability than conventional ultra-high strength steel. QP steel has a medium yield ratio and relatively high work hardening properties, and is suitable for body frame parts and safety parts with relatively complex shapes and high strength requirements.
3.11 stretcher strain marks
Due to the aging effect, the steel plate or the steel strip is unevenly deformed during the cold forming process, resulting in local plastic deformation of the steel plate or the steel strip, and finally a series of defects, such as parallel-line- like pleats or irregular fold lines, irregular surface distortions, that impair the quality of the surface appearance will be present on the surface of the steel plate or the steel strip.
3.12 coating mass
The sum of the mass of two sides of coating, expressed in the form of the mass of each side of coating, in grams/square meter (g/m2).
7.4 Mechanical properties
7.4.1 Tables 5 to 14 specify the direction of the tensile specimen applies to steel plates and steel strips. The tensile specimen is the coated specimen.
7.4.2 For steel plates and steel strips of the grades DC51D+Z, DC51D+ZF, DD51D+Z, DC52D+ZF in Table 5, it shall be ensured that the mechanical
properties of steel plates and steel strips comply with the requirements of Table 5 within 1 month from the date of completion of manufacture. For steel plates and steel strips of other grades in Table 5, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the
requirements of Table 5 within 6 months from the date of completion of
manufacture.
NOTE. The date of issue in the product inspection document is usually specified as the date of completion of the manufacture of the product.
7.4.3 For steel plates and steel strips of the grades specified in Table 6, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the requirements of Table 6 within 1 month from the date of completion of manufacture.
7.4.4 For steel plates and steel strips of the grades specified in Tables 7 and 8, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the requirements of the corresponding table within 6 months from the date of completion of manufacture.
7.4.5 For steel plates and steel strips of the grades specified in Table 9, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the requirements of Table 9 within 3 months from the date of completion of manufacture.
7.4.6 For steel plates and steel strips of the grades specified in Table 10, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the requirements of Table 10 within 6 months from the date of completion of manufacture.
7.4.7 For steel plates and steel strips of the grades specified in Table 11, Table 12, Table 13 and Table 14, it shall be ensured that the mechanical properties of steel plates and steel strips comply with the requirements of the corresponding table within 3 months from the date of completion of manufacture.
7.4.8 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 Tables 5 to 14 will no longer characteristics.
7.9.4 Users shall select the appropriate surface treatment method according to their own product processing technology, coating method, coating equipment, etc., and minimize the storage time of steel plates and steel strips as possible. 7.9.5 Choosing a suitable surface treatment method can reduce the tendency of white rust and friction marks during transportation and storage, and at the same time improve the coating adhesion in the subsequent processing and protect the coating.
7.9.6 For products need subsequent processing of phosphating and coating, it is not recommended to use passivation.
7.9.7 For surface treatments containing oiling, the demand party shall ensure that the cleaning agent used in the degreasing equipment does not damage the quality of the coating.
7.9.8 If the user specifies the surface no treatment (U), it shall be indicated in the contract. The supply party will not bear the corresponding product quality responsibility for surface defects such as white rust, scratches and friction marks generated during handling, storage and use of this type of product. 7.9.9 The available surface treatment options are as follows.
7.9.9.1 Chromic acid passivation (C) and chrome-free passivation (C5). This surface treatment reduces white rust on the surface of products during
transportation and storage. In the case of chrome-free passivation, the hexavalent chromium substances that are harmful to human health in the
passivation film are restricted.
7.9.9.2 Chromic acid passivation + oiling (CO) and chrome-free passivation + oiling (CO5). This surface treatment further reduces white rust on the surface of products during transportation and storage. In the case of chrome-free passivation, the hexavalent chromium substances that are harmful to human health in the passivation film are restricted.
7.9.9.3 Chrome-free fingerprint resistance (N5). This surface treatment reduces white rust on the surface of products during transportation and storage, while the fingerprint-resistant film improves the sweat and stain resistance of the surface of electronic or electrical products. The chromium-free fingerprint- resistant film restricts the hexavalent chromium substances that are harmful to human health.
7.9.9.4 Self-lubrication (SL). This surface treatment reduces white rust on the surface of products during transportation and storage, while the self-lubricating less than 20 mm from the edge.
8.3 The tensile test shall be in accordance with Method B of GB/T 228.1. In order to improve the reproducibility of the measurement results, it is
recommended to use the beam displacement control method. The rate to
measure the yield strength is 5 % Lc/min (Lc is the parallel length of the specimen). The position of the specimen shall not be less than 50 mm from the edge.
8.4 The r value is calculated at 15 % strain. When the uniform elongation is less than 15 %, it is calculated at the strain value at the end of the uniform extension. The n value is calculated over a 10 % to 20 % strain range. When the uniform elongation is less than 20 % but not less than 12 %, the strain range for calculation is 10 % to the end of the uniform extension; when the uniform elongation is less than 12 %, the strain hardening index shall be reported as the true strain value calculated at the end point of the uniform elongation (nuniform extension = ??uniform extension).
8.5 When measuring the coating mass, it shall be sampled according to the position shown in Figure 1. The area of a single piece of specimen shall not be less than 5000 mm2.
8.6 Steel plates and steel strips shall be accepted in batches. Each inspection batch shall consist of steel plates and steel strips of the same grade, the same specification and the same processing state of not more than 30 tons. For steel strips weighing more than 30 tons, each steel coil constitutes an inspection batch.
8.7 The inspection item, specimen quantity, sampling method and test method of each batch of steel plates and steel strips shall comply with the requirements of Table 20.
8.8 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.
Table 20
Inspection item Specimen quantity (piece) Sampling method Test method
Chemical 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
GB/T 2975
Method B in GB/T 228.1
Plastic strain ratio
(r value) 1 or 3/batch GB/T 5027
Table A.4 Unit. mm
Nominal
thickness
Thickness tolerance at the following nominal widtha
Ordinary precision PT.A Advanced precision PT.B
??? 1200 > 1200 ~ 1500 > 1500 ??? 1200
> 1200 ~
1500 > 1500
0.30 ~ 0.40 ??0.06 ??0.07 ??0.08 ??0.045 ??0.050 ??0.060
> 0.40 ~ 0.60 ??0.06 ??0.08 ??0.09 ??0.050 ??0.060 ??0.070
> 0.60 ~ 0.80 ??0.07 ??0.09 ??0.11 ??0.060 ??0.070 ??0.080
> 0.80 ~ 1.00 ??0.09 ??0.11 ??0.12 ??0.070 ??0.080 ??0.090
> 1.00 ~ 1.20 ??0.11 ??0.13 ??0.14 ??0.080 ??0.090 ??0.110
> 1.20 ~ 1.60 ??0.15 ??0.16 ??0.18 ??0.090 ??0.110 ??0.120
> 1.60 ~ 2.00 ??0.18 ??0.19 ??0.21 ??0.110 ??0.120 ??0.140
> 2.00 ~ 2.50 ??0.21 ??0.22 ??0.24 ??0.140 ??0.150 ??0.170
> 2.50 ~ 3.00 ??0.24 ??0.25 ??0.26 ??0.170 ??0.180 ??0.190
a The tolerance of the thickness in the range of 10 m near the weld zone of the steel strip may exceed 50 % of the specified value. For products with a weight of double-sided coating of not less than 450 g/m2, the thickness tolerance shall be increased by ??0.01 mm.
A.1.5 The thickness tolerance requirements stricter than PT.B may be
negotiated at the time of ordering and indicated in the contract.
A.2 Width tolerance
A.2.1 For steel strips with a width of not less than 400 mm, the width tolerance shall comply with the requirements of Table A.5.
A.2.2 If the user requests the steel plates and steel strips to be delivered in running edge state, the width tolerance is 0 mm ~ +8 mm.
A.2.3 The width tolerance requirements stricter than PW.B may be negotiated at the time of ordering and indicated in the contract.
Table A.5 Unit. mm
Nominal width Width tolerance Ordinary precision PW.A Advanced precision PW.B 400 ~ 1200 +5 0
> 1200 ~ 1500 +6 0
> 1500 ~ 1800 +7 0
> 1800 +8 0
A.3 Length tolerance
NOTE. According to the shape and position of the steel plate, the strain type of the steel plate may be divided into the following categories.
Bow. Curving along all directions of the steel plate, either longitudinal (along the rolling direction) or transverse (perpendicular to the rolling direction);
Wave. Waves, rippling along the longitudinal direction of the steel plate; Edge wave. Waves along the edge of the steel plate;
Center buckle, centre fullness; full centre. Waves at the center of the steel plate, also known as center folds.
A.4.4 The flatness tolerance requirements stricter than PF.B may be negotiated at the time of ordering and indicated in the contract.
A.4.5 For steel plates with a specified minimum yield strength of not less than 360 MPa, the maximum flatness tolerance may be negotiated between the
supply and demand parties at the time of ordering.
A.4.6 When the user has adequately leveled the steel strip, the values specified in Tables A.7 and A.8 also apply to the steel plates cut from steel strips by the user.
A.5 Out of squareness
A.5.1 Steel plates shall be cut at right angles.
A.5.2 The out of squareness (u) of steel plates may be measured by projection method or by diagonal method. When measured by the projection method, the out of squareness (u) is the vertical projection length of the wide side (width) of the steel plate to the longitudinal side (length) of the steel plate, as shown in Figure A.1. At this time, the out of squareness (u) shall not be more than 1 % of the actual width of the steel plate.
A.5.3 When measured by the diagonal method, the two diagonal lengths of the steel plate shall be measured, and 1/2 of the difference of the diagonal lengths shall be calculated, that is, u = |X1 - X2|/2, as shown in Figure A.2. At this time, the measured and calculated results shall not be more than 0.7 % of the measured width (W) of the steel plate.
A.5.4 When a dispute arises, projection method shall be used for arbitration. A.6 Edge camber
A.6.1 Edge camber (q) refers to the maximum distance between the side of the steel plate and steel strip and the line connecting the points at both ends of the HC220BD+Z, HC220BD+ZF 0.06 0.50 1.00 0.08 0.025 0.02 ??? ???
HC260BD+Z, HC260BD+ZF 0.11 0.50 1.00 0.10 0.030 0.02 ??? ???
HC300BD+Z, HC300BD+ZF 0.11 0.50 1.00 0.12 0.030 0.02 ??? ???
HC260LAD+Z, HC260LAD+ZF 0.11 0.50 0.60 0.025 0.025 0.015 0.15 0.09
HC300LAD+Z, HC300LAD+ZF 0.11 0.50 1.00 0.030 0.025 0.015 0.15 0.09
HC340LAD+Z, HC340LAD+ZF
HD340LAD+Z 0.11 0.50 1.00 0.030 0.025 0.015 0.15 0.09
HC380LAD+Z, HC380LAD+ZF 0.20 0.50 1.60 0.030 0.025 0.015 0.15 0.09
HC420LAD+Z, HC420LAD+ZF
HD410LAD+Z 0.20 0.50 1.60 0.030 0.025 0.015 0.15 0.09
HC460LAD+Z, HC460LAD+ZF 0.20 0.50 1.70 0.030 0.025 0.015 0.15 0.09
HC500LAD+Z, HC500LAD+ZF 0.20 0.50 1.70 0.030 0.025 0.015 0.15 0.09
HD550LAD+Z 0.20 0.50 2.00 0.030 0.025 0.015 0.15 0.09
a Ti and Nb may be added individually or in combination. It may also add V and B, in which case the total content of these alloying elements is ??? 0.22 %.
Table C.4
Grade
Chemical compositiona (smelting analysis) % (mass fraction)
not more
than
Si
not more
than
Mn
not more
than
not more
than
not more
than
Alt
not less
than
Ti a
not more
than
(B240P1D+Z)
(B240P1D+ZF) 0.10 0.50 1.80 0.10 0.025 0.015 0.20
(B260LYD+Z)
(B260LYD+ZF) 0.25 0.30 1.50 0.035 0.025 0.015 ???
a Allow part or all of Ti to be replaced by Nb, in which case the total content of Nb and Ti is ??? 0.20. Table C.5
Grade
Chemical compositiona (smelting analysis) % (mass fraction)
not more than
not more
than
Si
not more
than
Mn
not more
than
not more
than
not more
than
Alt
not less
than
Ti a
not more
than
(B240P1D+Z)
(B240P1D+ZF) 0.10 0.50 1.80 0.10 0.025 0.015 0.20
(B260LYD+Z)
(B260LYD+ZF) 0.25 0.30 1.50 0.035 0.025 0.015 ???
a Allow part or all of Ti to be replaced by Nb, in which case the total content of Nb and Ti is ??? 0.20. Annex D
(informative)
Comparison table of approximation between the grades of this
Technical Conditions and the grades of domestic and foreign technical
specifications
Table D.1
Q/BQB 420-2014 EN10346.2009 JISG3302.2012 ASTM A653M-13
DC51D+Z, DC51D+ZF
DD51D+Z DX51D
SGCC
SGHC CS Type C
DC52D+Z, DC52D+ZF DX52D SGCD1 CS Type A CS Type B
DC53D+Z, DC53D+ZF DX53D SGCD2 FS Type A, FS Type B
DC54D+Z, DC54D+ZF DX54D SGCD3 DDS Type C
DC56D+Z, DC56D+ZF DX56D SGCD4 DDS Type A
DC57D+Z, DC57D+ZF DX57D ??? EDDS
Table D.2
Q/BQB 420-2014 EN10346.2009 JISG3302.2012 ASTM A653M-13
S220GD+Z, S220GD+ZF S220GD ??? SS 230
S250GD+Z, S250GD+ZF S250GD SGC340 SS 255
S280GD+Z, S280GD+ZF S280GD SGC400 SS 275
S320GD+Z, S320GD+ZF S320GD ??? ???
S350GD+Z, S350GD+ZF S350GD SGC440 SS 340 class 4
S550GD+Z S550GD SGC590 SS 550 class 2
Table D.3
Q/BQB 420-2014 EN10346.2009 GMW 3032-2013 ASTM A653M-13
HC180YD+Z, HC180YD+ZF HX180YD CR180IF SHS180
HC220YD+Z, HC220YD+ZF HX220YD CR210IF SHS210
(B240P1D+Z), (B240P1D+ZF) ??? CR240IF SHS240
HC260YD+Z, HC260YD+ZF
(B240P1D+Z), (B240P1D+ZF) HX260YD ??? SHS280
HC180BD+Z, HC180BD+ZF HX180BD CR180B2 BHS180
HC220BD+Z, HC220BD+ZF HX220BD CR210B2 BHS210
HC260BD+Z, HC260BD+ZF HX260BD CR270B2 ???
HC300BD+Z, HC300BD+ZF HX300BD CR300B2 BHS300
HC260LAD+Z, HC260LAD+ZF HX260LAD CR270LA HSLAS-F 275
HC300LAD+Z, HC300LAD+ZF HX300LAD CR300LA -
HC340LAD+Z, HC340LAD+ZF
HD340LAD+Z HX340LAD
CR340LA
HR340LA HSLAS-F 340

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