GB/T 18984-2016 English PDF (GB/T18984-2016)

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GB/T 18984-2016: Seamless steel tubes for low-temperature-service piping
GB/T 18984-2016
Seamless steel tubes for low-temperature-service piping
ICS 77.140.75
H48
National Standards of People's Republic of China
Replacing GB/T 18984-2003
Low temperature seamless steel pipes
Published 2016-12-30
2017-09-01 implementation
Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
Standardization Administration of China issued
Foreword
This standard was drafted in accordance with rules GB/T 1.1-2009 given.
Instead of the standard GB/T 18984-2003 "cryogenic seamless steel pipe", compared with the GB/T 18984-2003, Technical change
Of the following.
--- modify the normative references;
--- modify the pipe ordering specifications;
--- modified pipe size tolerance;
--- modify the cut length tolerance;
--- modify the predetermined curvature;
--- increased 06Ni9DG grades;
--- modified steel phosphorus, sulfur content requirements;
--- modified steel smelting method;
--- modify the delivery status of steel;
--- modified flattening test applicable specifications and requirements determined;
--- modify the low magnification inspection requirements;
--- modified nonmetallic inclusions testing requirements;
--- modify the non-destructive inspection requirements;
--- revised set of rules approved.
The standard proposed by China Iron and Steel Association.
This standard by the National Steel Standardization Technical Committee (SAC/TC183).
This standard was drafted. Pangang Group Chengdu Steel and Vanadium Co., Ltd., Hengyang Valin Steel Tube Co., Ltd., Metallurgical Industry Information Standards Institute.
The main drafters. to Haitao, Wu Hong, Huang Pingjia, Zhao Bin, Dong Li, who Yonggang, Zhang San.
This standard supersedes the previous editions are.
--- GB/T 18984-2003.
Low temperature seamless steel pipes
1 Scope
This standard specifies the seamless steel pipes of low classification code, order contents, size, shape, weight, technical requirements, test methods,
Inspection rules, packaging, marking and certification.
This standard applies to -45 ℃ ~ -196 ℃ level stage cryogenic pressure vessel and the low temperature heat exchanger pipes seamless steel pipes.
2 Normative references
The following documents for the application of this document is essential. For dated references, only applies to the version dated paper
this. For undated references, the latest edition (including any amendments) applies to this document.
Chemical composition of the finished GB/T 222 steel tolerance
GB /Determination of soluble silicon steel and total silicon content T 223.5 reduced silicon molybdate salt spectrophotometric
GB/T 223.9 chromium alloy steel and the aluminum content was measured Azure S Spectrophotometry
GB/T 223.14 steel and tantalum alloys - spectrophotometric determination reagent vanadium content Cuiqu
GB/T 223.16 steel and alloys - Determination of Ti amount chromotropic acid
Determination of nickel content GB/T 223.25 steel and alloys - dimethylglyoxime gravimetric method
GB/T 223.26 thiocyanate salt spectrophotometric determination of molybdenum content alloy steel and
GB/T 223.40 Determination of the contents of alloy steel and niobium sulphochlorophenol S Spectrophotometry
GB/T 223.59 phosphorus content of steel and alloy measured by bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method
GB/T 223.63 steel and alloys - sodium periodate (K) for Determination of the amount of
Determination of sulfur content potassium iodate titration method after GB/T 223.68 and alloy steel pipe furnace combustion
GB/T 223.69 after the carbon content and alloy steel measuring tube furnace combustion gas volumetric method
GB/T 226 steel macrostructure defects and Etch Test Method
Rt Test Method. Part 1 Test GB/T 228.1 metal material tensile
GB/T 229 summer metallic materials than methods pendulum impact test
GB/T 241 Test Method metal hydraulic tube
GB/T 242 Test Method for expanding a metal tube opening
GB/T 244 Test Method for bending a metal pipe
GB/T 246 Test Method flattening the metal tube
GB/T 1979-fold structural steels and defect FIG.
Acceptance of GB/T 2102 steel, packaging, marking and certification
Sampling and sample preparation Test positions GB/T 2975 Mechanical properties of steel and steel products
GB/T 4336 carbon steel and low alloy steel for spark discharge atomic emission spectrometric method (conventional method)
GB/T 5777-2008 seamless steel ultrasonic testing method
GB/T 7735-2016 seamless and welded (except submerged arc) steel imperfections automatic eddy current testing
10561-2005 nonmetallic inclusions in steel content GB/T measurement standard rating FIG microscopic test method
Full-circumferential GB/T 12606-2016 seamless and welded (except submerged arc) ferromagnetic steel longitudinal and/or transverse imperfections automatic MFL
Detect
GB/T 17395 seamless steel pipe size, shape, weight and tolerance
GB/T 20066 Steel and iron chemical composition of the sample and the measurement sample preparation methods
GB/T 20123 total carbon and sulfur content of steel an induction furnace combustion infrared absorption method (conventional method)
GB/T 31925 walled seamless ultrasonic inspection methods
3 Classification and designation
3.1 Standard manufacturing seamless steel pipe by way divided into two categories and their code as follows.
a) hot rolling (expanded) steel, code for WH;
b) cold drawn (rolled) steel, code of WC.
After the letter 3.2 standard steel grades listed in "DG" is the first in capital letters are "low temperature" "pipe" pinyin.
4 ordering content
According to the standard steel pipe order contract or order shall include, but not limited to, the following.
a) the product name;
b) standard number;
c) steel grades;
d) Order number (or the total weight of the total length);
e) Dimensions;
f) the production method;
g) Special requirements.
5 size, shape and weight
5.1 diameter and wall thickness
5.1.1 well pipe nominal diameter (D) and the nominal wall thickness (S) shall comply with GB/T 17395's. According to the demand side, the supply and demand sides Association
Supplier, can supply pipe size than a predetermined GB/T 17395.
5.1.2 pipe diameter and wall thickness tolerance shall be as specified in Table 1. According to the demand side, the supply and demand sides negotiated, rules to produce Table 1
Outside tolerances given pipe size.
Table 1 pipe diameter and wall thickness tolerance in mm
5.2 length
5.2.1 usual length
Pipe length is generally 4000mm ~ 12000mm.
By agreement between the manufacturer and specified in the contract, the delivery can be shorter than the length of 4000mm but not less than short-foot steel pipe 3000mm, but
Their number should not exceed the total amount of steel batch delivery by 5%.
5.2.2 Length and double length
5.2.2.1 According to the demand side, the supply and demand sides negotiated, and in the contract, the pipe can be cut to length or double length delivery. Steel pipe set
Scale length and the total length of the double length should be within the range of usual length.
5.2.2.2 steel cut length tolerance shall be as follows.
a) length ≤6000mm, 0mm ~ 10mm;
b) a length> 6000mm, 0mm ~ 15mm.
5.2.2.3 Each double length should leave a notch below a predetermined margin.
When a) D≤159mm, cutout balance 5mm ~ 10mm;
b) D> When 159mm, slit balance 10mm ~ 15mm.
5.3 curvature
Bending the steel pipe should not exceed the following provisions.
a) S≤15mm, the curvature is not greater than 1.5mm/m;
b) S> 15mm ~ When 30mm, curvature is not greater than 2.0mm/m;
c) S> 30mm, or D≥351mm, curvature is not greater than 3.0mm/m.
5.4 tip shape
Pipe and pipe end faces at both ends should be perpendicular to the axis, the cutout burrs should be removed.
5.5 roundness and uneven thickness
According to the demand side, the supply and demand sides negotiated and specified in the contract, roundness and wall thickness of the pipe shall not exceed the outside diameter is not public
80% of the difference between the wall thickness and tolerances.
5.6 Weight
5.6.1 steel delivery by actual weight, also according to theoretical weight delivery. Theoretical calculation of the weight of steel required to GB/T 17395 (the steel
A density of 7.85kg/dm3).
5.6.2 Weight Tolerance
According to the demand side, the supply and demand sides negotiated and specified in the contract, allowing the deviation of the actual weight and the theoretical weight of the delivery pipe should
Comply with the following provisions.
a) a single steel tube. ± 10%;
b) minimum batch of steel 10t. ± 7.5%.
6 Technical Requirements
Grades and chemical composition of the steel 6.1
6.1.1 steel grades and chemical composition (melting analysis) should meet the requirements of Table 2, the acceptance by melting steel component. According to the buyer requirements, by
Supply and demand of both parties, and indicate in the contract, other steel grades can be used.
Table 2 Steel grade and chemical composition of the
6.1.2 demand side, product analysis, should be specified in the contract. The chemical composition of the finished steel tolerance should be consistent GB/T 222
Provisions.
6.1.3 steel content of residual elements shall be as follows. Cr≤0.25%, Cu≤0.20%, Ni≤0.40%, Mo≤0.08%.
6.2 Manufacturing Methods
6.2.1 outer arc furnace steel should be used by adding refining and outer vacuum refining process, or added oxygen converter refining and vacuum refining process. root
According to the demand side, the supply and demand sides negotiated and specified in the contract, but also use other methods of smelting.
6.2.2 rolled steel should be used (expanded) or a method for producing cold drawn (rolled).
6.3 Delivery status
6.3.1 addition 06Ni9DG steel, steel should be normalized, normalized or quenched and tempered and tempering state delivery. When the finish rolling temperature is not lower than the phase
Become critical temperature (Ar3), and passes through the steel pipe is air-cooled, shall be considered steel is the result of normalizing.
6.3.2 06Ni9DG steel should be quenched and tempered or normalized and tempered state secondary delivery.
6.4 Mechanical Properties
6.4.1 Mechanical Properties of longitudinal steel to comply with Table 3. Tensile test specimens shall conform to the model of Appendix A.
Table 3 Mechanical Properties of longitudinal steel
Lower yield strength or proof strength
A percentage elongation
a pipe outer diameter smaller than 20mm, a predetermined value in this table is not applicable percentage elongation, percentage elongation whose value is determined by agreement between the manufacturer.
When b is smaller than the wall thickness of 8mm steel, a tensile test sample No. 2, the wall thickness is reduced by a predetermined minimum value in this table should its percentage elongation of 1mm
Subtracting a minimum percentage elongation of 1.5%, in numerical integer rounding rule be rounded.
6.4.2 cryogenic pipe longitudinal Charpy V-notch impact absorption energy shall be as specified in Table 4. The impact test temperature shall comply with the following regulations
Set. 16MnDG, 10MnDG and 09DG was -45 ℃, 09Mn2VDG of -70 ℃, 06Ni3MoDG of -100 ℃, 06Ni9DG
As -196 ℃.
Table 4 Steel low temperature impact absorption energy of the longitudinal
Sample size (width × height) /
(Mm × mm)
Impact absorption energy a, bKV2/J
A group (3) the average of at least two of the individual values of a minimum value
10 × 10 ≥21 (40) ≥21 (40) ≥15 (28)
10 × 7.5 ≥18 (35) ≥18 (35) ≥13 (25)
10 × 5 ≥14 (26) ≥14 (26) ≥10 (18)
10 × 2.5 ≥7 (13) ≥7 (13) ≥5 (9)
It can not be used for a 10mm × 2.5mm steel sample size of impact, the impact absorbing energy is determined by the supply and negotiated.
B is a number in parentheses is the impact energy absorbing pipe 06Ni9DG.
6.5 Hydraulic
6.5.1 steel pipe hydraulic test should be carried out by the root. Pressure test according to formula (1) is calculated, the maximum test pressure of 10MPa. At a test pressure,
Regulator not be less than 5s, pipe leakage is not allowed.
P = 2SR/D (1)
Where.
P --- test pressure in megapascals (MPa);
S --- said well pipe wall thickness in millimeters (mm);
D --- male outer diameter of said pipe in millimeters (mm);
--- R and lt allowable stress, as specified in Table 3 at 60% of the yield strength in megapascals (MPa).
6.5.2 only for magnetic flux leakage inspection using eddy current inspection or testing instead of hydraulic. When a magnetic flux leakage inspection, an outer surface of the comparative sample tube longitudinal notch grooves
Shall comply with GB/T 12606-2016 F4 in the acceptance level; when the eddy current testing, comparative sample tube artificial defects should meet
Predetermined GB/T 7735-2016 E4H or E4 in the acceptance level.
6.6 Process Performance
6.6.1 crushed
Outer diameter larger than 22mm pipe flattening test should be done. Distance H calculated according to the formula (2) between the sample plate was flattened. Pressed to two sample
When the inter-plate is H, cracks or gaps are not allowed on the sample distance.
H --- distance between plates, in millimeters (mm);
S --- said well pipe wall thickness in millimeters (mm);
D --- male outer diameter of said pipe in millimeters (mm);
--- deformation coefficient per unit length [alpha], was 0.08.
6.6.2 bent
According to the buyer requirements, the agreement between manufacturer, and in the contract, the outer diameter of less than 40mm steel bending test may be performed. bending
Bend radius test was six times the nominal outer diameter of the steel pipe, the bending angle is 90 °, the sample after bending crack or cracks are not allowed.
6.6.3 flaring test
According to the buyer requirements, the agreement between manufacturer, and in the contract, the outer diameter no greater than 150mm and a wall thickness of not more than 10mm steel
Test tube may be flared. Mandrel Test flaring taper of 60 °, the outer diameter of the flaring of the specimen shall be as specified in Table 5, the sample that is not flared
Permitting le...