Hot rolled steel for oil and gas engineering

statement

This article is about studying GB-T 42678-2023 hot-rolled steel for oil and gas engineering. The study notes are compiled and shared in the hope that more people will benefit. If there is any infringement, please contact us in time.

1 Scope

This document specifies the ordering content, grade representation method, size, shape, weight, technical requirements,

Test methods, inspection rules, packaging, marking and quality certificates.

This document is applicable to hot-rolled
H-shaped steel, angle steel, etc. with flange (or edge) thickness not greater than 50 mm for onshore and offshore oil and gas engineering.

Channel steel and other shaped steel (hereinafter referred to as "shaped steel").

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, for dated referenced documents
, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

this document.

GB/T 222 Allowable deviations in chemical composition of finished steel products

GB/T 223.5 Determination of acid-soluble silicon and total silicon content in iron and steel Reduced silicomolybdate spectrophotometry

GB/T 223.9 Determination of aluminum content in steel and alloys Chromium Azure S Spectrophotometry

GB/T 223.12 Methods for chemical analysis of steel and alloys
- Sodium carbonate separation-diphenylcarbazide photometric method for determination of chromium content

GB/T 223.14 Methods for chemical analysis of steel and alloys - Determination of vanadium content by tantalum reagent extraction photometry

GB/T 223.17 Methods for chemical analysis of steel and alloys - Determination of titanium content by diantipyrine methane photometry

GB/T 223.19 Chemical analysis method for steel and alloys - Determination of copper content by new cuproline-chloroform extraction photometry

GB/T 223.23 Determination of nickel content in steel and alloys by diacetyl oxime spectrophotometry

GB/T 223.26 Determination of molybdenum content in steel and alloys Thiocyanate spectrophotometry

GB/T 223.37 Determination of nitrogen content in steel and alloys by distillation and separation of indophenol blue spectrophotometry

GB/T 223.40 Determination of niobium content in steel and alloys by chlorosulfenol S spectrophotometry

GB/T 223.62 Methods for chemical analysis of steel and alloys - Determination of phosphorus content by butyl acetate extraction photometric method

GB/T 223.64 Determination of manganese content in steel and alloys by flame atomic absorption spectrometry

GB/T 223.72 Gravimetric method for determination of sulfur content in steel and alloys

GB/T 223.78 Methods for chemical analysis of steel and alloys - Curcumin direct photometric method for determination of boron content

GB/T 223.86 Determination of total carbon content of steel and alloys - Infrared absorption method after combustion in induction furnace

GB/T 228.1 Tensile testing of metallic materials Part 1: Room temperature test method

GB/T 229 Charpy pendulum impact test method for metal materials

GB/T 232 Bending test method for metal materials

GB/T 706 hot rolled steel

GB/T 2101 General provisions for acceptance, packaging, marking and quality certificates of section steel

GB/T 2975 Sampling location and sample preparation for mechanical property testing of steel and steel products

GB/T 4336 Determination of multi-element content in carbon steel and medium-low alloy steel
Spark discharge atomic emission spectrometry (conventional method)

GB/T 8170 Numerical rounding rules and representation and determination of limit values

GB/T 11263 Hot-rolled H-shaped steel and split T-shaped steel

GB/T 20066 Methods for sampling and preparation of samples for determination of chemical composition of steel and iron

GB/T 42678—2023

GB/T 20123 Determination of total carbon and sulfur content in steel and iron by high-frequency induction furnace post-combustion infrared absorption method (conventional method)

GB/T 20124 Determination of nitrogen content in iron and steel - Inert gas melting thermal conductivity method (conventional method)

GB/T 20125 Determination of multi-element content in low alloy steel by inductively coupled plasma atomic emission spectrometry

GB/T 41749 General requirements for surface quality of hot-rolled steel sections

GB/T 42899 Test method for weldability of marine engineering structural steel

YB/T 4811 Ultrasonic testing method for hot-rolled H-shaped steel

YB/T 4932 Magnetic particle testing method for hot rolled steel

3 Terms and definitions

There are no terms or definitions to be defined in this document.

4 Order contents

Contracts or orders based on this document include but are not limited to the following:

a) product name;

b) This document number;

c) Brand number;

d) Model and specifications;

e) Delivery length;

f) weight and quantity;

g) Delivery status;

h) Other special requirements put forward by the buyer, such as special specification requirements, special surface quality requirements, etc.

5. How to express the brand number

The steel grade consists of the first letter
Q in Chinese Pinyin, which represents the yield strength "Qu", the specified minimum upper yield strength value, and the "Petroleum"

"Natural gas" consists of five parts: the first letter "YQ" in Chinese Pinyin of "oil and gas", the delivery status code, and the quality grade symbol (C, D, E, L).

Note: When the delivery status is hot rolling, the delivery status code can be omitted. When the delivery status is normalizing rolling, the delivery status code is
represented by N. The delivery status is thermal engine.

When mechanical rolling, the delivery status code is represented by M.

Example:

Q355YQND, where:

Q — The first letter of the Chinese Pinyin representing "Qu" for yield strength;

355 - the specified minimum yield strength value, in megapascals (MPa);

YQ—the first letter of the Chinese Pinyin of the abbreviation "oil and gas";

N — The delivery status is normalized rolling;

D — The quality level is D.

6 Dimensions, appearance, weight

6.1 Cross-sectional size, cross-sectional area, theoretical weight, cross-sectional characteristic parameters

The cross-sectional dimensions, cross-sectional area, theoretical weight, and cross-sectional characteristic parameters of the section steel shall comply with the
provisions of GB/T 706 or GB/T 11263.

Products of other specifications and models can also be supplied after negotiation between the supplier and the buyer and as indicated in the contract.

GB/T 42678—2023

6.2 Dimensions, shapes and allowable deviations

The size, shape and allowable deviation of section steel shall comply with the provisions of GB/T 706 or GB/T 11263.

6.3 Delivery length

The delivery length of the section steel should be specified in the contract, usually the fixed length is 12000 mm.
After negotiation between the supply and demand parties and stated in the contract, it can also

Other cut-to-length products are available. The length allowable deviation shall comply with
the provisions of GB/T706 or GB/T 11263.

6.4 Weight

6.4.1 Section steel is usually delivered according to theoretical weight, and the density of steel is calculated as 7.85 g/cm³
. After negotiation between the supplier and the buyer and noted in the contract, delivery can also be based on actual weight.

6.4.2
When delivered according to the theoretical weight, the calculation method of the allowable deviation of the weight of the section steel is the difference between the actual weight and the theoretical weight of a single piece or each batch divided by the theoretical weight
, expressed as a percentage. The allowable weight deviation of a single piece or batch of section steel shall comply with
the provisions of GB/T 706 or GB/T 11263.

7 Technical requirements

7.1 Brand and chemical composition

7.1.1 The grade and chemical composition (smelting analysis) of steel should comply with the provisions of Table 1 and Table 2.

Table 1 Steel grades and chemical composition

Trademark	Chemical composition (mass fraction)/%
	C	And	Mn	Cr	In	Cu	Mo	Nb²	V	Ti"	Nh	Al
Q275YQ	≤0.16	≤0.55	0.50~ 1.50	≤0.25	≤0.70	≤0.30					≤0.012	≥0.018
Q355YQ	≤0.16d	≤0.55	1.00~ 1.65	≤0.25	≤0.70	≤0.30	≤0.08	0.005~ 0.050	0.01~ 0.12	0.006~ 0.025	≤0.012	≥0.018
Q390YQ	≤0.164	≤0.55	1.00~ 1.65	≤0.25	≤0.70	≤0.30	≤0.10	0.010~ 0.050	0.01~ 0.12	0.006~ 0.025	≤0.012	≥0.018
Q420YQ	≤0.164	≤0.55	1.00~ 1.65	≤0.25	≤0.70	≤0.30	≤0.25	0.010~ 0.050	0.01~ 0.18	0.006~ 0.025	≤0.012	≥0.018
Q460YQ	≤0.164	≤0.55	1.00~ 1.65	≤0.25	≤0.70	≤0.30	≤0.25	0.010~ 0.050	0.01~ 0.18	0.006~ 0.025	≤0.012	≥0.018
Except for the Q275YQ grade, other grades of steel should contain at least one of the three elements Nb, V, and Ti. When added alone or in combination, it should be ensured that the content of at least one of the alloying elements is not less than the lower limit specified in the table. ; And when these three elements are added in combination, w(Nb+V+Ti) should be satisfied ≤0.22% requirement. b If the acid-soluble aluminum (Al,) content in the steel is not less than 0.015% or the total aluminum (Al,) content is not less than 0.018%, or other nitrogen-fixing alloy elements are added, the nitrogen element There is no limit on nitrogen content, but nitrogen-fixing elements should be stated on the quality certificate. When any one of the three elements Nb, V, and Ti is intentionally added to the steel, there is no requirement for the lower limit of the Al content. For quality grades E and L, the carbon content can be less than or equal to 0.14% according to the buyer's requirements.

GB/T 42678—2023

Table 2 Phosphorus content and sulfur content limit requirements

Trademark	quality level	wp/%	ws*/%
Q275YQ、Q355YQ Q390YQ Q420YQ Q460YQ	C	≤0.030	≤0.025
	D	≤0.030	≤0.020
	E	≤0.025	≤0.015
	L	≤0.025	≤0.015
When a transverse impact test is required, the sulfur content (mass fraction) of Class C, Class D, Class E, and Class L should not exceed 0.018%, 0.015%, 0.012%、0.010%。

7.1.2 The allowable deviation of the chemical composition of finished steel products shall comply with the provisions of GB/T 222.

7.1.3 The carbon equivalent (CEV) of steel
should comply with the provisions of Table 3. When the carbon content is not greater than 0.12%, welding crack sensitivity (Pcm) should be used
instead of carbon equivalent to evaluate the weldability of steel. The Pcm value should comply with the table 3 regulations. CEV
is calculated from the melting analysis components according to formula (1), and Pcm is calculated from the melting analysis components according to formula (2):

CEV=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 ( 1)

Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B ( 2 )

Table 3 Carbon equivalent and welding crack sensitivity index of steel (based on smelting analysis)

Trademark	CEV(mass fraction)/%	Pcm(mass fraction)/%
Q275YQ	≤0.40
Q355YQ	≤0.43	≤0.24
Q390YQ	≤0.43	≤0.24
Q420YQ	≤0.45	≤0.24
Q460YQ	≤0.45	≤0.26

7.2 Smelting methods

Steel should be smelted by oxygen converter or electric arc furnace and refined outside the furnace.

7.3 Delivery status

Section steel is delivered in hot-rolled or normalized rolling or thermo-mechanical rolling state, and the delivery status should be indicated on the quality certificate.

7.4 Mechanical properties and process properties

7.4.1 The mechanical properties and process properties of the section steel in the delivery state should comply with the requirements in Table 4.

GB/T 42678—2023

Table 4 Mechanical properties and process properties

Trademark	quality grade	Upper yield strength R²/MPa ≥				Tensile strength Rm/MPa	断后 伸长率 A/% ≥	R/R… ≥	夏比(V型缺口) 冲击试验
		公称厚度/mm							试验温 度/℃	冲击吸收能量 纵向KV₂/J ≥
		≤16	>16～25	>25～40	>40
Q275YQ	C	275	265	255	245	430～580	23	0.85	0	50
	D								-20	50
	E								-40	50
	L								-50	50
Q355YQ	C	355	345	345	335	470～630	22	0.87	0	50
	D								-20	50
	E								-40	50
	L								-50	50
Q390YQ	C	390	380	360	340	490～650	21	0.88	0	50
	D								-20	50
	E								-40	50
	L								-50	50
Q420YQ	C	420	400	390	380	500～660	19	0.90	0	50
	D								-20	50
	E								-40	50
	L								-50	50
Q460YQ	C	460	440	420	415	520～700	17	0.90	0	50
	D								-20	50
	E								-40	50
	L								-50	50
当屈服不明显时，可用规定塑性延伸强度R 代替上屈服强度R。 只适用于用户有强屈比特殊需求时。 型钢的冲击试验取纵向试样，经供需双方协商并在合同中注明，也可取横向试样，横向冲击吸收能量最小值由 供需双方协商确定。

7.4.2 公称厚度不小于6 mm 的型钢应做冲击试验，冲击试样尺寸取10
mm×10 mm×55 mm 的标准 试样；当型钢不足以制取标准试样时，应采用7.5
mm×10mm×55 mm 或 5 mm×10 mm×55 mm 小
尺寸试样，冲击吸收能量应分别为不小于表4规定值的75%或50%,应优先采用较大尺寸试样。

7.4.3
型钢的冲击试验结果按一组3个试样的算术平均值进行计算，允许其中一个实验值低于规定
值，但不应低于规定值的70%。

GB/T 42678—2023

7.5 弯曲试验

7.5.1
根据需方要求，并在合同中注明，钢材可进行弯曲试验，其指标应符合表5的规定。

7.5.2 如供方能保证弯曲试验合格，可不做试验。

表 5 弯曲试验

公称厚度 mm	180°弯曲试验
≤16	D=2a
>16～50	D=3a
D——弯曲压头直径，a——试样厚度。

7.6 焊接性能

对于翼缘(或边)厚度40 mm
及以上的型钢，经供需双方协商，并在合同中注明，可进行型式焊接试

验，焊接试验方法可按 GB/T42899, 焊接质量由供需双方协商。

7.7 无损检测

对于翼缘(或边)厚度12 mm
及以上的型钢，经供需双方协商，并在合同中注明，可按 YB/T 4811、

YB/T 4932
进行无损检测，其检验数量、检验频次、合格级别由供需双方协商并在合同中注明。

7.8 表面质量

7.8.1 型钢的表面质量应符合GB/T 706 或 GB/T 11263 的规定。

7.8.2 经双方协商，并在合同中注明，型钢的表面质量可按GB/T 41749
的规定执行。

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