Welding Hardox And Weldox - A&E Mach

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Welding Hardox and Weldox

The contents of this brochure represent general suggestions. SSAB AB accepts no responsibility for their suitability inindividual cases. The user is therefore responsible to make the necessary adaptations to the conditions in each individual case.

Welding of Weldox and Hardox The extreme performance of Weldox high strength steel and Hardox wear plateis combined with exceptional weldability. Any conventional weldingmethod can be used for welding these steels to any type of weldable steel.This brochure is aimed at simplifying, improving and boosting the efficiency ofthe welding process. It offers good advice on preheat and interpasstemperatures, heat input, welding consumables, shielding gas and a great dealmore. The aim is to enable every user to gain full benefit of the uniqueproperties of Weldox and Hardox.

Important parameters in weldingClean the joint to remove foreign matter such as moisture and oil residue before welding. In addition togood welding hygiene, the following items are important: Preheat and interpass temperature Heat input Welding consumables Shielding gas Weld sequence and gap size in the jointPreheat and interpass temperaturesThe right preheat and interpass temperature is important in order to avoid hydrogen cracking.Our recommendations are given in the table on the next page.Influence of alloying elements on the choice of preheat and interpass temperaturesA unique combination of alloying elements optimizesthe mechanical properties of Weldox and Hardox. Thiscombination governs the preheat and interpass temperature of the steel during welding, and can be usedto calculate the carbon equivalent value. The carbonequivalent value is usually expressed as CEV or CET inaccordance with the equations below.CEV  C  Mn (Mo Cr V) (Ni Cu) [%]6155The alloying elements are specified in the inspection certificate of the plate and are stated in percent by weightin these formulas. A higher carbon equivalent usuallyrequires a higher preheat and interpass temperature.Typical values of carbon equivalents are given in ourproduct data sheets.CET  C  (Mn Mo) (Cr Cu)Ni [%]102040Hydrogen crackingDue to their low carbon equivalents, Weldox and Hardox are better able to resist hydrogen cracking than manyother high strength steels. The risk of hydrogen cracking will be minimized if our recommendations are followed.Two rules for avoiding hydrogen cracking:1. Minimize the hydrogen content in and aroundthe prepared joint2. Minimize the stresses in the weld joint Use the right preheat and interpasstemperature Do not use welding consumables of a higherstrength than is necessary Use welding consumables with a lowhydrogen content Arrange the weld sequence so that theresidual stresses are minimized Keep impurities out of the weld area Set the gap in the joint to a maximum of 3 mm

Preheat and interpass temperatures for Weldox and HardoxThe lowest preheat and interpass temperature during welding is shown in the chart below. Unless otherwise stated,these values are applicable for welding with unalloyed and low-alloyed welding consumables. When plates of different thicknesses, but of the same steel grade are welded together, the thickest platedetermines the required preheat and interpass temperature. When different steel types are welded together, the plate requiring the highest preheat temperaturedetermines the required preheat and interpass temperature.MINIMUM RECOMMENDED PREHEAT AND INTERPASS TEMPERATURES FOR DIFFERENT SINGLE PLATE THICKNESSES [mm]3102030Weldox 70050607075 CWeldox 900*Weldox 960*408090120130100 C75 C100 C100 C75 CWeldox 1030*Weldox 1100*Weldox 1300*125 C100 CHardox HiTuf125 C100 CHardox 40075 CHardox 450175 C100 C125 CHardox 500150 C175 CHardox 550125 C175 CHardox 600150 C175 C200 C200 CHardox 600100 CHardox Extreme100 CStainless steel consumablesStainless steel consumablesRoom temperature (approx. 20 C)200 COutside the size rangeOnly stainless steel consumablesNote: The table is applicable to single plate thickness when welding with a heat input of 1.7 kJ / mm.Further information on single plate thickness can be found in TechSupport #61 at www.ssab.com.Maximum recommended interpass temperatureWeldox 700**300 CWeldox 900**300 CWeldox 960**300 CWeldox 1030200 CWeldox 1100200 CWeldox 1300200 CHardox HiTuf**300 CHardox 400225 CHardox 450225 CHardox 500225 CHardox 550225 CHardox 600225 CHardox Extreme100 Ct1 t 2 (dimensions in mm)The single plate thickness in thetable is t1 or t 2, provided that thesame steel type is used.t 1 t 2 (dimensions in mm)The single plate thickness in thetable is t1 or t 2, provided that thesame steel type is used.t1 t 2 (dimensions in mm)In this case, the single plate thickness in the table is t 2,provided that the same steel typeis used.* The consumables determine the preheating temperature if its carbon equivalent is higher than that of the plate.** Interpass temperatures of up to approx. 400 C can be used in certain cases for Weldox 700–960 and for Hardox HiTuf. In such cases, use WeldCalc.

If the ambient humidity is high or the temperature isbelow 5 C, the lowest recommended preheat temperatures given on the previous page should be increased by25 C. This also applies to firmly clamped weld jointsand if the heat input is 1.0 kJ / mm.The lowest recommended preheat and interpasstemperatures in the chart on the previous page are notaffected at heat inputs higher than 1.7 kJ / mm.The information is based on the assumption that thewelded joint is allowed to cool in air.Note that these recommendations also apply to tackwelds and root runs. Each of the tack welds should be atleast 50 mm long. The distance between tack welds canbe varied as required.Attaining and measuring the preheat and interpass temperatureThe required preheat and interpass temperature can beachieved in several ways. Electric preheater elementsaround the prepared joint are often best, since theyprovide uniform heating of the area. The temperatureshould be monitored by using, for example, a contactthermometer.Measure the preheattemperature here75 mmIntendedweld jointMeasure the temperature of the thickest plate in the joint. If the plate is 25 mmthick, measure the temperature 2 minutes after heating. If the plate is 12.5 mmthick, measure the temperature after 1 minute, etc. The interpass temperaturecan be measured in the weld metal or in the immediately adjacent parent metal.Using preheater elements

Heat inputWelding with the recommended heat input results in good mechanical properties inthe heat affected zone (HAZ)The heat supplied by the welding process affects themechanical properties of the welded joint. This isdescribed by the heat input (Q) that can be calculatedusing the formula below.xx I x 60Q k  Uv x 1000Q Heat input [kJ/mm]U  Voltage [V]I  Current [A]v Welding speed [mm/min]k Thermal efficiency [dimensionless]Different methods of welding have varying thermalefficiency (k). See the table below for approximatevalues of this property.Thermal efficiencyk [dimensionless]MMAMAG, all typesSAWTIG0.80.81.00.6Effects of heat input on a weld joint Better toughness Increased strength Reduced deformation Lower residual stresses Narrower HAZReduced heat inputIncreased heat input Higher productivity forconventional weldingmethods

Our recommendations for Weldox high strength steel are based on typical values for toughness in the HAZ beingat least 27 J at -40 C. The demands on toughness in the weld joints in Hardox wear plate are often lower.The recommendations for Hardox should therefore be regarded as approximate values.11 mmWhen a joint comprising different plate thicknesses is welded, the recommendedheat input is based on the thinnest plate in the welded joint.20 mmIn this case, the permissible heat input is basedon the 11 mm plate thickness.RECOMMENDED MAXIMUM HEAT INPUT FOR WELDOX, BASED ON THE LOWEST PREHEAT TEMPERATURE BEING USED:4,0Qmax Weldox 7003,5Qmax Weldox 900Qmax Weldox 9603,0Qmax Weldox 1030Qmax Weldox 1100Heat input [kJ/mm]2,5Qmax Weldox 13002,01,51,00,50,00510152025303540 –130Plate thickness [mm]RECOMMENDED MAXIMUM HEAT INPUT FOR HARDOX4.0Hardox3.5Heat input [kJ/mm]3.02.52.01.51.00.50.005101520Plate thickness [mm]25303540-130

Welding at higher elevated temperaturesHigher elevated temperatures that may occur, for instance in multipass weld joints, affect the recommended heatinput. The figure below shows the recommended heat inputs for joint temperatures of 125 C and 175 C.RECOMMENDED MAXIMUM HEAT INPUT FOR THE JOINT TEMPERATURE OF 125ºC4,0Qmax Weldox 7003,5Qmax Weldox 900Qmax Weldox 960–13003,0Heat input te thickness [mm]RECOMMENDED MAXIMUM HEAT INPUT FOR THE JOINT TEMPERATURE OF 175ºC4,0Qmax Weldox 7003,5Qmax Weldox 900Qmax Weldox 960–13003,0Heat input [kJ/mm]2,52,01,51,00,50,00510152025303540 –130Plate thickness [mm]The WeldCalc computer program can be used for preheat and interpass temperatures above 175 C.WeldCalc has been developed by SSAB by our world leading experts on the welding of heavy plate.The program can be ordered free of charge at www.ssab.com.

Welding consumablesUnalloyed, low-alloyed and stainless steel consumables can be used for the welding of Weldox and Hardox.Strengths of unalloyed and low-alloyed welding consumablesThe strength of the welding consumables should betoughness and the resistance to hydrogen cracking.selected in accordance with the figure on the next page.The carbon equivalent value of consumables with aUsing low-strength consumables can offer several benyield strength 700 MPa may be higher than that of theefits, such as higher toughness of the weld metal, higher plates.resistance to hydrogen cracking and lower residualWhen there are different recommended preheat temstresses in the weld joint. In multipass joints in Weldoxperatures for the joint materials and the consumables,700–1300, it is particularly beneficial to weld with con- then the highest value should be used. Hardox shouldsumables of different strengths. Tack welds and the first be welded with low strength consumables as shown inthe figure on the following page.passes are welded with low strength consumables andthen high strength consumables are used for the remainder of the passes. This technique can increase both theWelding consumables with higher strengthWelding consumables with lower strengthWelding consumables with higher strengthWelding consumableswith lowerstrengthHydrogencontentofunalloyed and low-alloyed welding consumablesThe hydrogen content should be lower than or equalto 5 ml of hydrogen per 100 g of weld metal whenwelding with unalloyed or low-alloyed welding consumables. Solid wires used in MAG and TIG weldingcan produce these low hydrogen contents in the weldmetal. The hydrogen content for other types of weldingconsumables can best be obtained from the respectivemanufacturer.Examples of consumables are given at www.ssab.com in the publication TechSupport #60. If consumables are stored in accordance with the manufacturer’srecommendations, the hydrogen content will be maintained at the intended level. This applies, above all, tocoated consumables and fluxes.

Recommendedstrength ofconsumables forhighly stressed jointsWelding consumables, EN classR p0.2 [MPa]Recommended strength ofconsumables for otherjointsMMASAWMAGMAGTIG(solid wire/flux combinations)(solid wire)(all types of tubularcored wires)900EN 757E 89 XEN ISO 26304 (-A) S 89XEN ISO 16834 (-A) G 89XEN ISO 18276 (-A) T 89XEN ISO 16834 (-A) W 89XEN 757E 79 XEN ISO 26304 (-A) S 79XEN ISO 16834 (-A) G 79XEN ISO 18276 (-A) T 79XEN ISO 16834 (-A) W 79XEN 757E 69 XEN ISO 26304 (-A) S 69XEN ISO 16834 (-A) G 69XEN ISO 18276 (-A) T 69XEN ISO 16834 (-A) W 69XEN 757E 62 XEN ISO 26304 (-A) S 62XEN ISO 16834 (-A) G 62XEN 757E 55 XEN ISO 26304 (-A) S 55XEN ISO 2560E 50 X800700EN ISO 16834 (-A) W 62X600500EN ISO 16834 (-A) G 55XEN ISO 18276 (-A) T 55XEN ISO 16834 (-A) W 55XEN 756S 50XEN ISO 14341 (-A) G 50XEN ISO 16834 (-A) T 50XEN ISO 636 (-A) W 50XEN ISO 2560 (-A)E 46 XEN 756S 46XEN ISO 14341 (-A) G 46XEN ISO 16834 (-A) T 46XEN ISO 636 (-A) W 46XEN ISO 2560 (-A) E 42 XEN 756S 42XEN ISO 14341 (-A) G 42XEN ISO 16834 (-A) T 42XEN ISO 636 (-A) W 42XWeldox 1300Weldox 1100Weldox 1030Weldox 960Weldox 900Weldox700Hardox HiTufHardox 400Hardox 450Hardox 500Hardox 550Hardox 600400Note that X may stand for one or several characters.Welding consumables, AWS classR p0.2 [MPa]Recommendedstrength ofconsumables forhighly stressed jointsRecommended strength ofconsumables for otherjointsMMASAW(solid wire/flux combinations)MAGMAGMAG(solid wire)(flux coredwire)(metal coredwire)TIG900800AWS A5.5E120XAWS A5.23F12XAWS A5.23F11XAWS A5.28 ER120S-XAWS A5.29E12XT-XAWS A5.29E11XT-XAWS A5.28 E120C-XAWS A5.28ER120XAWS A5.28ER110X700AWS A5.5E110XAWS A5.28E110C-XAWS A5.28 ER100S-XAWS A5.5E100XAWS A5.5E90XAWS A5.5E80XAWS A5.5E70XAWS A5.23F10XAWS A5.28 ER110S-XAWS A5.29 E10XT-XAWS A5.28 E100C-XAWS A5.28ER100XAWS A5.23F9XAWS A5.28 ER90S-XAWS A5.29E9XT-XAWS A5.28E90C-XAWS A5.28ER90XAWS A5.23F8XAWS A5.28 ER80S-XAWS A5.29E8XT-XAWS A5.28E80C-XAWS A5.28ER80XAWS A5.23F7XAWS A5.28AWS A5.29E7XT-XAWS A5.28E70C-XAWS A5.28ER70X500Weldox 1300Weldox 1100Weldox 1030Weldox 960Weldox 900Weldox700Hardox HiTufHardox 400Hardox 450Hardox 500Hardox 550Hardox 600400ER70S-XNote that X stands for one or several characters.

Stainless steel welding consumablesConsumables of austenitic stainless steels can be usedfor the welding of all our products. They allow weldingat room temperature ( 20 C) without preheating,excluding Hardox 600, as shown in the chart.We recommend giving first preference to consumables in accordance with AWS 307 and second preferenceto those in accordance with AWS 309. These types ofconsumables have yield streghts up to approximately500 MPa in all the weld metal. The AWS 307 type canwithstand hot cracking better than AWS 309. It shouldbe noted that manufacturers seldom specify thehydrogen content of stainless steel consumables, sincehydrogen does not affect the performance as much as itdoes in unalloyed and low-alloyed consumables. Suggestions for various stainless steel consumables are given atwww.ssab.com in the publication TechSupport #60.Stainless steel welding consumables, EN classMMASAWMAGMAG(solid wire)(solid wire)(all types ofcored wires)First preference:EN ISO 14343-A: B 18 8 Mn/EN ISO 14343-B: SS307First preference:EN ISO 14343-A: B 18 8 Mn/EN ISO 14343-B: SS307First preference:EN ISO 17633-A: T 18 8 Mn/EN ISO 17633-B: TS307First preference:EN ISO 14343-A: W 18 8 Mn/EN ISO 14343-B: SS307Second preference:EN ISO 14343-A: S 23 12 X/EN ISO 14343-B: SS309XSecond preference:EN ISO 14343-A: B 23 12 X/EN ISO 14343-B: SS309XSecond preference:EN ISO 17633-A: T 23 12 X/EN ISO 17633-B: TS309XSecond preference:EN ISO 14343-A: W 23 12 X/EN ISO 14343-B: SS309XTIG500All Weldox andHardox steelsFirst preference:EN 1600: E 18 8 MnSecond preference:EN 1600: E 19 12 XNote that X may stand for one or several characters.Stainless steel welding consumables, AWS classMMASAWMAG(solid wire)MAG(solid wire)(flux cored wire)MAGTIG(metal cored wire)All Weldox andHardox steels500AWS 5.4 E307-XAWS 5.9 ER307AWS 5.9 ER307AWS 5.22 E307T-XAWS 5.9 EC307AWS 5.9 ER307Note that X stands for one or several characters.Hard facingsHard facing with special consumables increases thewear resistance of welded joints. Both the instructionsfor the consumables used and the ordinary recommendations for Weldox and Hardox should be followed.It is beneficial to weld a buffer layer with extra hightoughness between the ordinary welded joint or plateand the hard facing. The choice of consumables for thebuffer layer should follow the welding recommendationsforWeldox and Hardox steels. Stainless steelconsumables in accordance with AWS 307 and AWS309 should preferably be used for the buffer layer.HardfacingSteel substrateBuffer layer

Shielding gasThe choice and mixture of shielding gases is dependent on the welding situation and Ar and CO2 arethe most commonly used.Effects of various shielding gas mixtures Facilitates striking ofthe arc Reduced spatter Low amount of oxidesAr (inert gas)Ar/CO2(active gas) CO2 Stable arc Low porosity More weld spatter/cloggingof the welding nozzle High penetration of theweld metalExamples of shielding gas mixtures are given below.Welding methodArc typeShielding gas (volume %)MAG, solid wireMAG, metal cored wireShort arcAr 15-25 % CO2MAG, solid wireMAG, metal cored wireSpray arcAr 8-25 % CO2MAG, flux cored wireShort arcAr 15-25 % CO2, or pure CO2MAG, flux cored wireSpray arcAr 8-25 % CO2MAG, all typesAll arc typesAr 15-25 CO2TIGPure ArIn all welding methods based on shielding gas, the flow of shielding gas is dependent on the welding situation.A general guideline is that the shielding gas flow in l / min should be set to the same value as the inside diameter ofthe nozzle measured in mm.Weld sequences and gap sizeTo avoid hydrogen cracks in the weldedjoint: The starting and stopping sequences should not belocated in a corner. If possible, the starting andstopping procedures should be at least 5–10 cmfrom a corner.Max. gap of 3 mm The gap in the weld joint should be a maximumof 3 mm.Max. gap of 3 mm

Welding on the Weldox and Hardox primerWelding can be carried out directly on the excellentWeldox and Hardox primer, due to its low zinc content.The primer can easily be brushed or ground away inthe area around the joint. Removing the primer priorto welding can be beneficial, as it can minimize theporosity in the weld and can facilitate welding inpositions other than the horizontal.If the primer is left on the weld preparation, theporosity of the weld metal will be slightly increased.The MAG welding process with flux cored wire and theMMA welding process offer the lowest porosity.As in all welding operations good ventilation mustbe maintained, then the primer will not have a harmfuleffect on the welder and his surroundings.For further information, download TechSupport #25from www.ssab.com.For best possible results, the primer can be removed.Post weld heat treatmentHardox HiTuf and Weldox 700–960 can be stress relieved by post weld heat treatment, although this isseldom necessary. Other Weldox and Hardox steels should not use this method for stress relieving, sincethis may impair the mechanical properties.For further information, see the Welding Handbook from SSAB. This can be ordered at www.ssab.com.

SSAB employs over 8 700 people in over 45 countries around the world and operatesproduction facilities in Sweden and the US. SSAB is listed on the NASDAQ OMXNordic Exchange, Stockholm.For more information, contact us or visit www.ssab.comSSABSE-613 80 OxelösundSwedenT 46 155 25 40 00F 46 155 25 40 73E . Österbergs & Sörmlandstryck, Nyköping.SSAB is a global leader in value added, high strength steel. SSAB offers productsdeveloped in close cooperation with its customers to reach a stronger, lighter andmore sustainable world.

The extreme performance of Weldox high strength steel and Hardox wear plate is combined with exceptional weldability. Any conventional welding method can be used for welding these steels to any type of weldable steel. This brochure is aimed at simplifying, improving and boostin

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