Heat Treatment

COOPERHEAT 25

INTRODUCTION

TO HEAT

TREATMENT OF WELDED STRUCTURES AND TECHNICAL DATA

1. Welding Process The welding process applied to metals joins two components together by fusion. The surfaces to be joined are raised locally to melting point by a source of heat provided by a variety of welding methods based on electric arc, electric resistance, flame. The process energy creates a localised molten pool into which the consumable is fed, fusing with the component surfaces and/or previously deposited weld metal. As the molten pool is moved along the joint axis, the components are heated, nonuniformly and subsequently cooled, also non-uniformly. Neighbouring elements of material try to expand and contract by differing amounts in accordancee with the sequence of the localised thermal cycle. Characteristically the cooling weld metal contracts under conditions of severe restraint, leading to the introduction of thermally induced stresses. As contraction tries to take place and the stress system strives to reach its lowest level to achieve stability, distortion will occur as yielding takes place. If the joint is restrained and cannot distort, then high levels of stress will occur and may lead to failure in the form of cracking.

Br

its Effects

A longitudinal force on the weld is required to close the gap giving a tensile stress whilst corresponding compressive stresses in the plate material provide the equilibrium.

Fused Weld Metal

Residual stresses will act in two principle directions; longitudinal stresses parallel to the joint and transverse stresses normal to the joint.

I /./ Residual Stress Directions

The distribution of longitudinal residual stresses in the section will be as shown with tensile component confined to the region of the joint.

Stress Distribution

It should not be forgotten that the value of the tensile stresses can be high often exceeding yield point magnitude. Unrestrained Contraction Causes Distortion

In making a joint, gaps would occur at the plate ends if the weld metal were allowed to expand and contract without restraint.

I1I Unfused Weld Metal

'as cast' type of structure develops. In the region of parent metal at the fusion face raised to melting point, metallurgical restructuring takes place to give the heat affected zone (HAZ).

So far the mechanical effects of welding in the form of residual stresses have been considered. The deposition of weld metal in a molten pool and the localised melting of the joint faces of the components, along with subsequent cooling, all have metallurgical implications affecti ng the microstructu re of these regions. Cooling after welding can be relatively rapid. From the molten pool of weld metal an

OJ

Weld Metal 0 HAZ Parent Plate

o

In steel the heat affected zones are generally harder than the parent material with corresponding loss of ductility and resistance to impact. Since the basic sources of weld failure are a consequence of thermal behaviour, a series of potential solutions arise based on the application of heat. The welding processes have to be controlled so that the residual stresses are minimised to protect the integrity ofthe overall fabrication and the metallurgical structures of the weld metal and heat affected zones are controlled to give properties which are not inferior to those of the parent material which have been used in the design of the product. A series of heat treatment operations are associated with the welding processes, arising from the need to control these changes. These form the basis of the subject of Heat Treatment Engineering.

2. Preheat

Br

Postheat

Preheating involves raising the temperature of the parent material locally, on both sides of the joint to a value above ambient. The need for preheat is usually determined by the pertinent fabrication code and verified by the weld procedure qualification test. Preheat may be required as an aid to welding for one of four basic reasons. • To control the rate of cooling, especially in the heat affected zone, to reduce hardness. High carbon and low alloy steels harden if they are quenched from high temperatures (above cherry red). Exactly the same process can happen in a welded joint at the fusion face with the parent material. 8y raising the temperature of the base metal to be welded, to reduce the temperature differential between ambient and the resultant heat input, hardening may be contr911ed as the weld cools. Reducing hardness reduces the risk of cracking.

~>\~~:~/.(~ ~

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tffY..~ -~~--~--=====::_--------

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- RED •.·.~f;.; •••"•..• ~ -HOT FILE QUENCHEO

.-.,~ .. ,. "~ //.\\\""

IN~'ATER

BECOMES HARD

RED HOT FILE COOLED SLOWLY BECOMES MALLEABLE AND DUCTILE

:1/ Mater;al Hardens

\

Ome

ocl~ Material Softens

• To control the diffusion rate of hydrogen in a welded joint. The intensity of the electric welding arc breaks down water, present as moisture, into its base elements of hydrogen and oxygen. 80th of these gases are easily dissolved into the weld metal at high temperatures and hydrogen can play an important role in weld and heat affected zone cracking with a phenomenon known as hydrogen or cold cracking. Preheat can also help by ensuring that the weld

preparartion area is dry and remains dry throughout the welding operation. The presence of preheat, and associated benefits on cooling rate, helps to facilitate the diffusion of the hydrogen molecules out of the metallic structure.

i:=l~ L:J \ ~

OXYGEN

HYDROGEN

• Compensation for heat loss. Thicker section steels with high thermal conductivity benefit from preheat during welding with improved fusion. Where preheat is applied, every effort should be made to ensure that the correct levels for a particular application are attained, both uniformly over the length of the joint and for the duration of the welding process. Thick Section

Thin Section

'///J///.

Heat Loss

Low

Porosity

Heat Affected Zone (Haz)

Moisture is also introduced from the welding consumables being present in electrode coatings and fluxes. To obtain the maximum benefits from preheat in controlling hydrogen, it must be accompanied by careful controls over removal of moisture from the welding consumables by following manufacturers baking and storage instructions.

• To reduce thermal stresses. Thermal strains are set up as the molten weld pool cools. Partially made welds can crack as the parent metal restrains the contraction of the weld metal and the cross sectional area of the joint is insufficient to with stand the resfJltant stress. Preheat can control the level of strain by reducing temperature differentials and reducing cooling rates. The solid curve shows the temperature in the heat affected zone as the arc passes by

The dotted curve is the temperature

when

preheat

slower

is used. Preheating

provides

cooling

Time

----..

--

~

~ High

Guidance for the need to preheat is generally obtained from the national fabrication codes, which will list recommended minimum temperatures for steel types grouped by composition and also relate the minimum section thickness to which they apply. For the purposes of illustration, the preheat requirements of high pressure pipework codes 8S2633, ANSI 831.1, and ANSI 831.3 are compared.

Post Heat This is the term given to the extension of preheat on completion of welding at the same or increased temperature. Its purpose is to effect diffusion of hydrogen from the joint and reduce susceptibility to the associated form of cracking. It is usually applied to the higher strength carbon managenese steels and the low alloy steels where the risk of hydrogen cracking is higher. Post heat treatments are not reflected in national standards or codes, but are often specified by the client who has incorporated their equivalent into the weld procedure qualification test. The temperatures and soak times are derived from numerous technical papers published on this topic.

27

2.5

An estimate of weld metal root run not run. All diameter PREHEAT BS 2633: 1987· 20'C 50'C 100'C 150'C All 5'C 5'Cto 30mm 100'C 30 thickness 5'C 12.5mm thick diameter or thickness and thicknesses 127mm thickness 200'C Material Minimum steel Material allowed Carbon Steel All Above 20 Above 12.5 thickness weld metal metal18S 1719) 12.5 Up 30mm (greatest preheat hydrogen levels can be made 12.5 38 -200'C 20'C Up 5'C to 30 ofI jointcontrolled mm I FOR weld temp (greatest Matching root Non hydgrogen Hydrogen controlled 12.5 Not permissable 20 ofREQUIREMENTS joint mm Low H1rods required from a knowledge ofUp the Above30mm Above 12.5 to 20 Up to 0.40%C 7Cr'I)Mo preheat temperature potential hydrogen level in theMinimum Carbon-moly Carbon steel consumables

I r~XI

Low

I

I

Medium

HIGH PRESSURE PIPEWORK

High

Weld hydrogen level

Special

Note re 8S.2633

The table is for guidance only. It illustrates the contents of the preheat section of BS. 2633 (Table 5) which should be consulted in its entirety. A number of other important standards give guidance on preheat, these include:

Hydrogen-induced cracks in HAZ of a butt weld

ASME Code

Section III : Nuclear power plant components Section VIII: ASME Boiler and pressure vessel code

BS 1113

Water tube steam generating plant

BS 4570

Fusion welding of steel castings Part 1 - Production, rectification and repair Part 2 - Fabrication welding

BS 5135

Metal arc welding of carbon and carbon-manganese steels

BS 5500

Unfired fusion welded pressure vessels

Special

Note re ANS1/B31-1

Br

ANS1/B31-3

The table below is for guidance only. Reference should be made to the appropriate specification

Weldmg

at sub-zero

temperatures

Minimum Recommended Temperature 'F Group causes increased residual stress PREHEAT REQUIREMENTS PETROLEUM REFINERY PIPING (ANSI B.31-1.19901 Carbon Steel AN 71 SI 8.31.3 & below Others ANS1831.1 1" - above 50 - -50 27 Chromium 300 200 50 300 400 Carbon 0.30% 1" -175 50 300 3 175 350 00KSI P-9A 250. P98 -Preheat 300 8%,9% Nickel Alloys Nickel Ferritic '/1% max 71 KSI & FOR below '/{ 50 OR -above 175 Manganese High Chromium Chromium Alloy Austenitic Martensitic 2'/4% Vanadium '1)%-2% - 10% Above 60 KSI or both '/{'/{ -or 250 '/1" & chromium above 6% - 400 Metal Material Number 3 10E P21-P52 - 300 Above 1" &&above -175 175~::sne~ 50 group above 171 KSI - -175 ~;:;~~;~~~'8ase Others 120%

'I{

11

100

0

1

100

200

300

400·C

Weld hydrogen level Effect of preheating

on

residual

stresses

& POWER PIPING (AN SI B31.1-1992)

3. Post Weld Heat Treatment Post Weld Heat Treatment. This is a process commonly referred to as stress relief, so called because it is carried out at temperatures at which yield strength has fallen to a low value. If the structure is heated uniformly, the yield strength of the material around the weld is unable to support the initial deformation. Creep occurs at the elevated temperatures and strain will occur by a diffusion mechanism, relaxing the residual stresses even further. The extent to which residual stresses are relaxed will depend on temperature for any given material and on material for any given temperature. The stress distributions at the higher temperatures become more uniform and their magnitude reduces to a low level. On cooling, provided it is carried out in a controlled manner, the improved stress distribution is retained. In addition to a reduction and re-distribution of residual stresses, postweld treatments at higher temperatures permits some tempering or aging effects to take place. These metallurgical changes are very beneficial in that they reduce the high hardness of the as-welded structures, improving ductility and reducing the risks of brittle fracture. Post weld heat treatment has mandatory significance governed by the national standards and codes, as well as being required to offer acceptable component life in onerous environments. As with preheat, the alloying content of the steel is related to the significance of heat treatment temperature. Features of Post Weld Heat Treatment. There are five aspects to a post weld heat treatment that must be addressed. The hot zone is adequate to raise the weldment to the

required temperature and provide a temperature profile therein which is uniform without creating additional undue thermally induced stresses. This aspect has greater significance in the case of localised heat treatments, but nevertheless must also be considered with furnace heat treatments.

engineered system is capable of providing appropriate levels of performance. Benefits of Post Weld Heat Treatment

~

100%

"c:

"il; ~~

29

80%

"-~ ",0>

The heating and cooling rates are at least compliant with the necessary code requirements. These rates will indicate absolute maximum values, and are calculated from simple formulae related to component thickness to offer protection against thermally induced stresses. With thicker and more complex structures an experienced heat treatment engineer may wish to consider lower rates than required by the code to ensure acceptable temperature profiles and gradients with a view to keeping these thermally induced stresses to an absolute minimum. With localised heat treatment, the temperature gradients away from the hot zone must not be unduly severe, again the objective being the minimisation of thermally induced stresses. British Standards BS 5500, BS 2633 offer guidence in this issue, quoting the 2.5 Rt rule.

~~ "'-

60%

~

40%

~~ "-~ -0 Q3

-

co

'" ~

o

Complete relief of residual stresses

20%

-J

0%

700

200

The heat treatment system (including insulation), zonal division and number of thermocouples is such that the energy input and level of control is capable of enabling these objectives to be met ensuring that the integrity of the overall structure is not jeopardised. For local heat treatments, controls have to be implemented to provide assurance that the

400

500

600

Effect of stress relieving at various temperatures Reduced

Residual

Stresses

i '" '" '"

c:

-0 "-

co

J::

Improved

Metallurgical

Structure

Postheated Weld

Weld not Postheated

-V

The soak tempertures are held within the upper and lower limits of the soak range for the appropriate period of time.

300

Stress relieving temperature ("C)

Improved

Corrosion

Resistance

Remove

~qr~w~~~¥' U PWHT

Improved

Machinability

.

POSTWELD HEAT TREATMENT FOR 2633: 590-620 None 630-670 680-720 720-760 60) 60) 710-760 120) 2.5 5 (minimum (minimum 120) 1201 301 (minimum 30) 580-620 Local heattreatment (weldsSSonly) wall thickness 60) Not required 1801 (optimum creepl 2.5 {minimum 601 thin wall up 180) Not required 630-670 180 irrespective of thickness but REQUIREMENTS thin wall up to to 127mm 127mm Soaking Temperature in601 furnace (pipework and welds)

not required) 9Cr lMo 12CrMoV(WI

where

Time at temperature:

Minutes/mm

1987 - HIGH PRESSURE PIPEWORK

thickness

o

Special Note re BS.2633 The table is for guidance only. It illustrates the contents of the post weld heat section of SS. 2633 (Table 6) which should be consulted in its entirety. Also see SS. 1113 for post weld heat treatment requirements for water tube steam generating plant. For certain service conditions and for pipes of O.15%OCmaximum, post weld heat treatment of welds in pipes up to and including 12.5mm thick and fillet welded attachments where the throat thickness does not exceed 12mm is not required subject to satisfactory welding procedure tests. Special Note re ANSI/B31·1

& ANSI/B31·3

The table below is for guidance only. Reference should be made to the appropriate specification

Postweld Treatment Requirement of 0.15% Soak Carbon Steel POST WELD HEAT TREATMENT REOUIREMENTS FOR PETROLEUM 9% nickel steel None None Above 1350/14502 2" 1025/10851 hours min. 1350/14251 1300/1400 1400/14751 1 hour{lnch hour 241 Brinell (note: hour/inch hour{lnch hourlinch max 1225/13001 hour min1250/1300 1Boiler hour {Inch Manganese vanadium Nickel alloy steels ANSI B.31.3 Chromium alloy austenitic ferritic martensitic 2'/4% '12% '/2% -2% max - 10% 3/t 31{ 3/4' 3/"-1100 '/2"Heat -1100/1200 or 0.15% above 71 KSll100/1300 -11751 carbon, 71 Above 9A 1toKSI KSI-1300/1375 above hour hour 3% -min 3/t 'h", 5/s" '12".4" 1100/1325 min min chromium '/{, 1100/1200 & 4" Carbon 00,0.15% 4 OD, above 1 hour carbon carbon 0.25% {Inch. 3% 130011375 1100/1200 chromium High Chromium AN SI B3.1 External Piping cooling rate be above 300/Hr down to 600) Material Group 1 225 Brinell 112",1100 max 1 hour hour min. min. 9B - above - 1175

'I{ -

ll Base max 0/1225 llA

PIPING (ANSI B.31.1. 1990) & POWER PIPING (AN SI B31.1-1992)

Heat Treatment of Pipewelds with 48kV A Heat Treatment Unit and Pad Elements

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a

31

Cl:

lJ..

Cl:

~ Cl:

®

415V 3 PHASE 60 AMP SUPPLY

®

CIRCUIT 1

CIRCUIT 2

® Note: 'Circuits 3, 4, 5 and 6 have not been shown for clarity.

TYPICAL 48kVA 6 Unit CHANNEL 1 32002 3Cable 143007 32001 42011 6 15 Stock No. 10334 4 11 2 22 9 2 48kV 35024 A 6Oty. Channel Heat Treatment Unit 12-18 1Elements 9 Sets See 4175617 As Range Req. Page Description Thermocouple Attachment Triple 3 See way Heating Range Splitter Cables 2 2m Ceramic High Thermocouple Temperature Fibre Insulating with Cement Plug Mats

ed will depend on extent of work and production rate.

® ®

HEAT TREATMENT

UNIT PACKAGE

Circumferential Stress Relief of Pressure Vessel Welded Seams using Twin Bulkhead Method and Channel Elements .

CABLE ENTRY THROUGH VESSEL 'MAN-WAYS'

• @ ROLLER SUPPORTS FOR EXPANSION

FIXED SUPPORTS

6 CHANNEL 415V DISTRIBUTION UNIT AND TEMPERATURE RECORDER

STEEL BULKHEADS 4-12mm RODS IRON MESH WIRED TO BULKHEADS

THERMOCOUPLES ATTACHED TO WELDED SEAM AND AT GRADIENT POSITIONS

J

•

4-BANK CHANNEL ELEMENTS

n n

TYPICAL RECOMMENDED HEIGHT FOR MILD STEEL CHANNELS

MILD STEEL CHANNELS TO SUPPORT ELEMENTS

MINERAL WOOL MATS 60mm THICK WITH SINGLE LAYER OVER GRADIENT ZONES AND DOUBLE LAYER OVER THE HEATED ZONE

TYPICAL PACKAGE FOR PWHT OF 3M DIAMETER 12 34000 6 1 40006 Stock 27750 96' 43007 22 18 No. 32002 3 1 9 14002 30001 12 1 11 10 10 Bales 506-014 42011 2 19 9 Mineral 19 Wool 41756(7 As Req. 64-Bank Channel 415V Distribution Unit Thermocouple Attachment Qty. Channel Page Elements Description (31 Phase) 6 Point Temperature Recorder (11 Phase) 3 way Splitter Cable 2m 30m Thermocouple Compensating with Cable Plug (2Unit Ptsl Heater) High Temperature Cement (4/3Insulation Heating Elements) Feed Cable

SEAM

Temperature Conversion Tables Example Find the known temperature to be converted in the Red column. Then read the Centigrade conversion to the left and Farenheit to the right

98.9

204

400

752

therefore 400'C 400'F

752'F 204'C

244 241 224 1120 214 210 2642 2660 1670 2678 2714 2696 1724 1652 1688 662482 680488 698493 716499 3650 1470 3668 3686 1490 1480 1460 900 910 920 930 940 2030 350 360 370 380 390 793 1099 799 1110 804 2606 2624 2570 1616 1580766 1634 608466 626471 590460 644477 3578 3560 3596 1420 1410 1430 1440 870 880 860 890 1960 1990 320 330 310 340 1071 771 777 1082 782 1088 2534 1544 554449 572454 1390 1400 840 850 1950 290 300 754 760 1066 1526 2516 1508 2498 1380 1370 830 820 1930 1920 280 270 743 1049 1054 2480 1472 1490 482427 3452 1350 1360 800 810 1910 250 260 1043 478.4416 2426 2444 1454 3416 3398 1330 1320 1340 780 770 790 1890 248 247 249 727 712 716 1032 1310 760 246 471.2 496.4 2372 2354 1382 3344 3326 1300 1290 1280 750 740 730 1850 1840 245 243 399 704 1010 699 1004 693 467.7 465.8 2318 1328 3290 1270 1260 1820 720 710 242 377 682 993 460.4 2282 2264 2246 1292 1274 1256 3254 3236 3218 1250 1240 1230 1220 700 1800 690 1790 680 1780 670 240 239 238 237 354 677 671 666 982 977 971 451.4332 455.0343 2174 2210 1220 3146 3164 3182 1180 1190 1200 1210 630 1740 640 650 660 1760 235 236 233 234 654 960 1994 1090 1640 540 588 893 444.2310 449.6327 447.8 2120 2138 2084 1130 1148 1112 3074 3092 1160 1170 1140 1150 610 620 1690 600 1710 590 1700 231 229 232 230 627 632 616 932 921 422.6243 424.4249 433.4277 420.8238 417.2227 437.1288 428.0260 440.6299 431.6 442.4 1814 1076 2048 1958 1850 1868 1922 1022 896 986 914 824 878 842 950 2822 2804 2930 2876 2966 2894 3020 3038 1070 1030 1010 1020 1000 1060 1080 1050 1040 1100 1110 1130 990 1550 1540 1580 1600 1590 1680 570 1620 1560 1570 520 1610 460 470 450 480 530 1630 510 490 440 500 550 560 1660 580 1670 223 216 215 222 221 220 226 227 228 217 218 219 225 577 543 549 566 271 266 604 882 849 854 871 916 910 415.4221 413.6216 411.8210 1778 1742 788 770 2732 980 970 960 950 1510 1500 1530 1520 430 420 410 400 211 213 212 510 827 821 816 1706 734504 3632 3704 1450 2000 2010 2020 2040 788 1093 1104 1116 810 2588 1598 1614 1970 1980 1077 1562 2552 3542 3524 1940 1060 536443 518438 3506 3488 749 2462 500432 3470 1900 732 1038 738 476.6410 480.2421 2408 1436 1418 3434 1880 1870 1027 1021 474.8404 2390 1400 3380 1860 710 1016 473.0 2336 1364 1346 3362 1830 393 388 999 2300 1310 3308 1810 382 688 988 464.0 462.2 458.6 2228 1238 3272 1770 371 366 360 660 966 453.2338 456.8349 2156 2192 1166 1184 1202 3200 1730 1750 638 643 649 943 949 954 435.2282 446.0316 1004 1094 2102 2984 3110 3128 1720 321 621 938 927 426.2254 419.0232 438.8293 429.8 2012 2030 2066 1832 1940 1886 1976 1904 1040 1058 968 860 932 2948 2840 2858 2912 3002 3056 1650 538 571 554 582 560 532 304 593 599 610 843 838 877 860 888 866 899 904 410.0204 1795 1760 806 752 2786 2768 2750 527 521 516 832

33

Conversion Factors

Jkcal 0.948 kJ =0.155in2 35.27 ounce Area cm2 25.4 mm Ib Btu kW fr 3fr3OF-l 6.29 1.12 barrel acre MJ ton =0.0624Ib fr3 = 1.356J 1.609 159 litre km ft therm Ibf ft2 3.281 ft =1.163W =22051b =2.205Ib 30.48 cm + km2 m2 h-1 1Power, h-1m-3 =0.738 ft Ibf =3.60 =2.590 MJ km Jcal kWh mile2 2.471 1.055 28.32 1.102 acre kJ litre Btu ha ton =0.293 Wh 105.5 MJ =0.86 kcal m-2h-1OC-l 0.405 56.87 ha Btu min-1 0.0095 therm 0.86 lW =29.31 =0.093 kWh m2 =0.176 ft-2h-1 °F-l =99.8 =0.0149 0.239 Btu Ib-1 ft-3OF-1 °F-1 =0.239 =0.578 =6.93 =3412 =0.386 = 67.07 10.76 0.9144 35.31 0.621 Btu kcalh-1 Btu cal ft2 W mile2 kJmc ft3 mile m in h-1 ft-1 fr2h-1OF-1 30CWm-1OC-1 h-1OF-1 =0.394 in heatflow =4.187J =6.452cm2 0.0283 m3 Heat 1 Btufr' transfer ft-20F-1 h-1OF-l= coefficient =5.678 Wm-2OC-1 907 kg =220 0.264 0.4536 Imp US kg gal gal 0.984 Imp ton 6.23 Imp gal 7.48 US 264 US gal =0.556 deg C = =0.835Ib 0.3725 16.02kg 0.22 1016 kg hp lib m-3 (US hour (US gal)-l = Density 119.8 kg m-3 =42 1.8 deg US gal F= K 107 28.35 ergs g 11gal)-l 0.1 Ib (Imp 11 kg gal)m-3 Ib (Imp gal)-l Fm-2h-10C-1 Temperature intervals 11 deg C 1 Btu Btu Length Ib-10F-l =4.187 kJkg-1°C-l Wm-2OC-1 W m-2OC-1 Btu kcal = kg Thermal conductivity 2 F-1 = 0.144Wm-1°C-l 1.163 Wm1 kJkg-1°C-1 I 1 in20C-1

II

80 120 Wt. 30 10S 1.050 0.109 Std. Extra Outside 0.134 0.307 0.180 0.406 0.687 0.312 1.375 1.343 2.375 2.875 4.500 0.600 0.300 3.500 0.065 0.840 0.294 0.083 0.147 140 100 160 20 40 60 Sch. Double 0.065 0.133 0.308 0.358 0.113 0.179 1.315 0.109 0.156 0.750 2.062 0.140 0.552 0.145 0.200 0.400 0.154 0.218 0.436 0.203 0.382 0.226 0.318 0.718 0.593 0.365 0.250 0.165 0.330 0.843 0.500 1.125 0.237 0.337 0.674 0.258 0.280 0.864 0.148 0.812 0.322 0.277 0.875 0.375 0.438 0.937 1.259 1.438 0.562 1.562 1.500 1.281 1.812 1.531 0.191 0.276 1.000 1.312 0.432 0.906 0.750 1.406 0.656 1.218 1.031 1.593 1.156 1.781 0.968 1.093 1.968 1.660 1.900 4.000 10.750 12.750 5.563 6.625 8.625 14.000 16.000 18.000 20.000 24.000 0.083 0.120 0.216 Strong

5S 0.154 0.531 0.147 0.179 0.250 0.191 0.200 0.218 0.276 0.318 0.337 0.375 0.625 0.500 0.432 0.718 0.563 0.438 0.250 0.300

0.133 0.113 0.140 0.145 0.216 0.109 0.226 0.237 0.154 0.203 0.258 0.280

0.187 0.218 0.250 0.375 0.343 0.438 0.281

Specific 1.73Wm-1 0C- 1 heat capacity

rate

I

0.636

Wall Thickness Standard for (inches) Nominal Imperial Pipe Double

..

..•....

Engineering Data Physical Properties Of Typical Pressure Part Steels K-1.10-6 16.7520 19.2562 18.0541 18.7555 Wm-1.K-1 23 20 7970 14.6602 12.7503 13.8561 14.6611 13.8545 12.7511 38 49 7850 42 Coefficient Heat 25 17 33 43 36 20 Temperature Thermal Density Kg 20°C J.Kg-1.K-1 .m-3 to Temp Specific Conductivity

14 54 45

35

Tensile Properties Of Typical Pressure Part Steels 300 550 500 450 400 600 350 170 180 220 170 170 140 150 185 240 200 160 187 125 128 165 175 190 130 135 205 220 179 182 140 122 184 170 190 160 235 180 160 230 127 195 130 135 145 110 185 120 165 150 190 125 130 100 250 155 145 178 175 185 105 145 115 225 Carbon

Tensile 190temperatures 260 190 340 245195 230 245150 210 290 285 245 205 170 140200 245 275 280 215 Yield N 180 .mm-z 460 490 430 270190 510 540 225 440 420 480 0.2% Proof Stress (1% for Austenitic Steels) Strength at various °C N.mm-z

Steel Steel