sa-841

SPECIFICATION FOR STEEL PLATES FOR PRESSURE VESSELS,PRODUCED BY THE THERMO-MECHANICAL CONTROL PROCESS(TMCP)
SA-841/SA-841M
(Identical with ASTM Specification A841/A841M-90.)
1.Scope
1.1This specification covers steel plates produced
by the thermo-mechanical control process(TMCP).The
plates are intended primarily for use in welded pressure
vessels.
1.2The TMCP method consists of rolling-reduction
and cooling rate controls which result in mechanical
properties in thefinished plate that are equivalent to
those attained using conventional rolling and heat treat-
ing processes which entail reheating after rolling.A
description of the TMCP method is given in Appen-
dix X1.
1.3Due to the inherent characteristics of the TMCP
method,the plates cannot be formed at elevated tempera-
tures without sustaining significant losses in strength
and toughness.The plates may be formed and post-
weld heat-treated at temperatures not exceeding1200°F
[650°C],providing the requirements of6.1are met.
1.4The maximum nominal thickness of plates fur-
nished under this specification may not exceed4in.
[100mm].
1.5The values stated in either inch-pound units or
SI units are to be regarded separately as standard.
Within the text,the SI units are shown in brackets.The
values stated in each system are not exact equivalents.
Therefore,each system must be used independently of
the bining values from the two systems may
result in nonconformance with this specification.
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2.Referenced Documents
2.1ASTM Standards:
A20/A20M Specification for General Requirements for
Steel Plates for Pressure Vessels
A435/A435M Specification for Straight-Beam Ultra-
sonic Examination of Steel Plates
A577/A577M Specification for Ultrasonic Angle-Beam
Examination of Steel Plates
A578/A578M Specification for Straight-Beam Ultra-
sonic Examination of Plain and Clad Steel Plates for
Special Applications
3.General Requirements and Ordering
Information
3.1Material supplied to this material specification
shall conform to Specification A20/A20M.These
requirements outline the testing and retesting methods
and procedures,permissible variations in dimensions,
quality and repair of defects,marking,loading,etc.
3.2Specification A20/A20M also establishes the
rules for ordering information which should be complied
with when purchasing material to this specification.
3.2.1When the material is to be subjected to
warm forming or post-weld heat treatment,the order
must indicate the temperatures and times-at-temperature
that will be utilized in such operations.(See6.1and
Specification A20/A20M,Supplementary Require-
ment S3.)
3.3In addition to the basic requirements of this
specification,certain supplementary requirements are
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SA-841/SA-841M1998SECTION II
available when additional control,testing,or examina-
tion is required to meet end use requirements.These include:
3.3.1Vacuum treatment,
3.3.2Additional or special tension testing,
3.3.3Additional or special impact testing,and
3.3.4Nondestructive examination.
3.4The purchaser is referred to the listed supplemen-tary requirements in this specification and to the detailed requirements in Specification A20/A20M.
3.5If the requirements of this specification are in
conflict with the requirements of Specification A20/
A20M,the requirements of this specification shall prevail.
4.Manufacture
4.1Steelmaking Practice—The steel shall be killed and shall conform to thefine austenitic grain size requirement of Specification A20/A20M.
4.2The plates shall be produced by the thermo-mechanical control process.
5.Chemical Composition
5.1The chemical composition on heat analysis shall conform to the requirements listed in Table1,except
1422as otherwise provided in Supplementary Requirement S17of Specification A20/A20M when that requirement is involved.
5.2If a product analysis is made on a sample taken from the standard location(see Specification A20/A 20M),the results of the analysis shall not deviate from the limits for the heat analysis by more than the values given in Table2.
6.Mechanical Requirements
6.1When the material is to be subjected to warm forming or post-weld heat treatment,the test coupons shall be subjected to heat treatment to simulate such fabrication operations.(See3.2.1and Specification A 20/A20M,Supplementary Requirement S3.)
6.2Tension Test Requirements—The plates as repre-sented by the tension-test specimens shall conform to the requirements shown in Table3.
6.2.1Number and Location of Test Coupons—Two tension tests shall be made from each plate-as-rolled.One test coupon shall be taken from a corner of the plate on each end.
6.3Notch Toughness Test Requirements:
6.3.1Longitudinal Charpy V-notch tests shall be made in accordance with Specification A20/A20M.
6.3.2The test results of full-size specimens shall meet an average value of15ft·lbf[20J]at−40°F [−40°C].
PART A—FERROUS MATERIAL SPECIFICATIONS SA-841/SA-841M
TABLE1
CHEMICAL REQUIREMENTS
Element Composition,%
Carbon,max0.20
Manganese
tϹ1.5in.[40mm]0.70–1.35A
t>1.5in.[40mm] 1.00–1.60
Phosphorus,max0.030
Sulfur,max0.030
Silicon0.15–0.50
Copper,max0.35
Nickel,max0.25
Chromium,max0.25
Molybdenum,max0.08
Columbium,max0.03
Vanadium,max0.06
Aluminum,min0.020total or0.015acid soluble
A Manganese may exceed1.35%on heat analysis,up to a maximum
of1.60%,provided that the carbon equivalent on heat analysis does
not exceed0.47%,or the value specified in Supplementary Require-
ment S77when that requirement is invoked,when based on the follow-
ing formula.
CE p C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15%
When this option is exercised,the manganese content on product
analysis shall not exceed the heat analysis content by more than
0.12.%
TABLE2
PRODUCT ANALYSIS TOLERANCES
Tolerances,%
Under,Over,
Element Specified Limit Minimum Maximum
Carbon to0.15,incl0.020.03
over0.150.030.04
Manganese to0.60,incl0.050.06
over0.60to0.90,incl0.060.08
over0.90to1.20,incl0.080.10
over1.20to1.35,incl0.090.11
over1.35to1.65,incl0.090.12
Phosphorus to0.020,incl...0.005
over0.20...0.010
Sulfur to0.020,incl...0.005
over0.020...0.010
Silicon to0.30,incl0.020.03
over0.30to0.40,incl0.050.05
over0.400.060.06
Nickel to1.00,incl...0.03
Chromium to0.90,incl...0.04
Molybdenum to0.20,incl...0.01
Copper to1.00,incl...0.03
Vanadium to0.10,incl...0.01
Columbium to0.10,incl...0.01
Aluminum to0.15,incl0.0050.01
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SA-841/SA-841M1998SECTION II
98
TABLE3
TENSILE REQUIREMENTS
Elongation in
Yield Strength,Tensile Strength,Elongation in8in.,min,
Thickness min ksi[MPa]ksi[MPa]2in.,min,%%A
to2.5in.5070–902218
[to65mm]345[485–620]2218
over2.5in.4565–852218
[over65mm]310[450–585]2218
A See Specification A20/A20M for elongation adjustments.
SUPPLEMENTARY REQUIREMENTS
Supplementary requirements shall not apply unless specified in the order.
A list of standardized supplementary requirements for use at the option of the
purchaser are included in Specification A20/A20M.Several of those that are
considered for use with this specification are listed in this section by title.Other
tests may be performed by agreement between the supplier and the purchaser.
S1.Vacuum Treatment,
S2.Product Analysis,
S3.Simulated Post-Weld Heat Treatment of
Mechanical Test Coupons,
S5.Charpy V-Notch Impact Test,
S6.Drop Weight Test,
S7.High-Temperature Tension Test,
S8.Ultrasonic Examination in accordance with Specification A435/A435M,
S9.Magnetic Particle Examination,
S10.Charpy V-Notch Test Curve,
1424S11.Ultrasonic Examination in accordance with Specification A577/A577M,
S12.Ultrasonic Examination in accordance with Specification A578/A578M,
S13.NDT Temperature Determination,
S14.Bend Test(pin diameter subject to
agreement),
S17.Vacuum Carbon-Deoxidized Steel,
S18.Unspecified Elements,and
S19.Restricted Chemical Requirements.
PART A —FERROUS MATERIAL SPECIFICATIONS SA-841/SA-841M
ADDITIONAL SUPPLEMENTARY REQUIREMENT
Also listed is an additional supplementary requirement suitable for use with this specification.
S77.Carbon Equivalent Limit
S77.1The carbon equivalent,on heat analysis,shall not exceed the limits listed in this section when based on the following equation:
APPENDIX
(Nonmandatory Information)
X1.THERMO-MECHANICAL CONTROL
PROCESS (TMCP)X1.1Introduction —The Thermo-Mechanical Control Process,commonly referred to as “TMCP,”has evolved from the “controlled rolling”processes which have been known and used for a number of years.TMCP is the new generation of controlled rolling.TMCP produces fine-grained steel by a combination of chemical composition and integrated controls of manufacturing processes from slab reheating to post-rolling cooling,thereby achieving the specified mechanical properties in the required plate thicknesses.TMCP requires accurate control of both steel temperature and rolling reductions.X1.2Outline of TMCP —As shown in Fig.X1.1,TMCP may incorporate two processes,as follows:X1.2.1Thermo-Mechanical Rolling (TMR)—Steels of fine grain size are produced by rolling in the
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CE p C +Mn/6+(Cr +Mo +V)/5+(Cu +Ni)/15%
t p 2in.[50mm]and under in thickness 0.40%t p 2in.[50mm]in thickness 0.45%
recrystallization and the nonrecrystallization regions of austenite,and some-times in the dual-phase temperature region of austenite and ferrite.Generally,a high propor-tion of the rolling reduction is performed close to,or below,the temperature at which austenite begins to transform to ferrite during cooling (Ar3)and may involve rolling in the lower portion of the temperature range of the intercritical duplex phase region.X1.2.2Accelerated Cooling (AC)—Steels meeting the specified requirements are produced by promoting grain refinement and increasing the pearlite or bainite,or both,volume fraction through controlled cooling (accelerated cooling and air cooling)in the dual-phase temperature region immediately after the final controlled rolling (CR)or TMR operation.
X1.3The selection,from the above,of the method to be used is made by the plate producer depending upon the chemical composition,the plate thickness,and the required properties.
SA-841/SA-841M1998SECTION II
FIG.X1.1SCHEMATIC DIAGRAMS OF THERMO-MECHANICAL CONTROL AND CONVENTIONAL PROCESS OF
STEEL PLATE
1426。