Welder s Handbook new

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Air Products Welder s Handbook CONTENTS,Introduction. Fusion welding 2,Why use welding 3,Arc welding processes 4. Welding terms 5,MIG MAG welding 6,TIG welding 10,Plasma welding 17. Welding sheet 18,Welding plate 20,Welding pipes 22. Defects in welds 24,The right gas,MIG MAG welding 26.
TIG welding 29,Welding data,MIG MAG welding 30,Flux cored electrodes 33. TIG welding 34,Oxy fuel gas cutting 37,Plasma cutting 44. Safety always 46,Conversion data inside back cover. Air Products Welder s Handbook,Fusion welding T joint. The most widely used welding proc,esses rely on fusion of the components fillet.
at the joint line weld,In fusion welding a heat source melts. the metal to form a bridge between the,components,Two widely used heat sources are. high current,low voltage Butt joint butt,supply weld. Electric arc,fuel gas flame,air must be excluded,from heated area. The molten metal must be protected,from the atmosphere absorption of.
oxygen and nitrogen leads to a poor,quality weld,Air in the weld area can be replaced by. a gas which does not contaminate the,metal or the weld can be covered with. INTRODUCTION,Why use welding Which process, Welding is used because it is A large number of welding processes. and techniques are available No, one of the most cost effective process is universally best Each has. methods of joining metal its own special attributes and must be. components matched to the application,suitable for thicknesses ranging.
Choosing the most suitable process,from fractions of a millimetre to a. requires consideration of a number of,third of a metre. versatile being applicable to a,wide range of component. shapes and sizes, The joints produced by welding are Factors in choosing. permanent welding process,strong usually matching the.
strength of the components type of metal,leak tight type of joint. reproducible production constraints,readily inspected by non equipment availability. destructive techniques,labour availability,Welding can be used health safety and the. environment,in the workshop,costs of consumables,labour costs. material thickness,Air Products Welder s Handbook ARC WELDING.
Arc welding processes Two of the most important processes. use a gas shield to protect the weld,metal from atmospheric. Fabrications involving sheet metal,contamination,plate or pipes are commonly welded. by an arc process,WELDING TERMS, Terms commonly used in filler metal Metal added to the weld. pool during welding For TIG it is, gas shielded welding supplied as cut lengths of wire. interpass temperature The,arc length Distance between the tip.
temperature of the material adjacent to,of the electrode and the surface of the. the joint between each run is the,interpass temperature In some. base metal Incorrectly used to applications a maximum temperature. describe the metal from which the is specified to avoid metallurgical. components of the joint are made changes in the metal. The correct term is parent metal melt run Melting the parent metal. bead A single run of weld metal by passing a TIG arc along the. deposited onto the surface of the surface Filler metal is not used. parent metal nozzle In TIG and MIG MAG, burn off rate The rate at which the welding A metal or ceramic tube. wire is melted Quoted as a linear which confines the shielding gas to. measurement m min metres per the weld area, minute or in min parent metal The metal which is to. deposited metal Material which is be joined by welding Often incorrectly. added either from the electrode or called the base metal. filler wire to build up the weld profile pass or run The metal deposited. during one traverse of the joint by an,deposition rate The rate at which.
arc In TIG welding without a filler the,melted electrode metal is added to the. term melt run may be more correct,weld pool Quoted in kg hr kilograms. per hour Sometimes incorrectly preheat temperature The. temperature of the parent metal just, used in reference to the ratio of metal before welding is started With some. deposited to the amount of electrode metals the parent metal is heated. melted this is the deposition before,efficiency welding to avoid problems such as. cracking or lack of fusion,electrode The flux coated rod in.
manual metal arc welding the root run The first run deposited in a. tungsten in TIG and plasma welding joint where further runs are needed to. and the consumable wire in MIG MAG fill the groove. welding The arc is formed between sealing run A run of weld metal. the parent metal and one end of the deposited on the reverse side of a butt. electrode joint along the line of the root,Air Products Welder s Handbook. MIG MAG welding principles The shielding gas can be. pure argon,Gas shielded metal arc welding is a,argon mixed with small. semi automatic process which is,amounts of other gases. suitable for both manual and,mechanised operation helium or. carbon dioxide,It is known by a variety of names,according to the metal being welded.
MIG Metal Inert Gas,MAG Metal Active Gas,See pages 9 and 26. CO2 carbon dioxide,A low voltage 18 40V high current. 60 500A arc between the end of a,wire electrode and the work provides. the heat needed for the welding nozzle to plate,distance kept at. operation The arc and the weld are about 19 25mm,protected from atmospheric.
contamination by a gas shield,drive rolls keep constant. wire feed speed arc length,spool of wire,supply unit. work length,constant gas nozzle,shielding gas,MIG MAG WELDING. Operation overhead,An electric motor feeds the wire into. the arc and the power source keeps,the arc length at a preset value leaving.
the welder to concentrate on ensuring,complete fusion of the joint. Power sources for MIG MAG are,called constant voltage or potential vertical. known as the self adjusting arc and,constant current known as controlled. arc or drooping characteristic units, Modern power sources combine The appropriate technique for these. constant current and constant voltage types of joint is either Dip Transfer or. cc cv and are called inverters Pulse Transfer,These two techniques are also used.
for welding sheet material,Synergic MIG MAG is an advanced. welding system which incorporates,both spray and pulse transfer. Optimum conditions can be,established for a range of applications. which are readily reproduced by the,Special equipment is required for. Synergic MIG MAG welding,joints in flat position,Welding data for MIG MAG applica.
The process can be operated at tions are given on pages 30 to 33. currents within the range 280 500A for,welding plates thick walled pipes and. sections in the flat position The term,Spray Transfer is used to describe. this type of operation,MIG MAG welding with a,Ferromaxx gas shield gives a low. Welds which are located in positions hydrogen content in the weld This. where the metal tends to run out of the,means that lower preheat levels are. joint under the action of gravity are, welded at lower currents 60 180A needed than with MMA welding.
Air Products Welder s Handbook, Using MIG MAG welding Voltage controls the profile of the. weld Inductance in Dip Transfer,stabilises the arc and minimises. With MIG MAG the wire is pointed in,spatter Wire feed speed sets the. the direction of travel forehand,welding current,technique This allows the arc to fuse. the parent metal ahead of the weld,pool and gives the best penetration.
The welder controls the speed of travel high,to ensure that the weld pool does not correct. run ahead of the arc as this would low,cause lack of fusion. Weld quality in MIG MAG welding is,critically dependent on the skill of the. welder and selection of the welding,0 Current controls. heat input,size of weld,depth of penetration,Wire diameter depends on the current.
required The table gives a guide to,the selection of wire diameter but the. exact relationship depends on the,material and the shielding gas. Current Wire feed,Diameter range speed,mm A m min,0 6 40 100 2 5. 0 8 40 150 3 6,1 0 100 280 3 12,1 2 120 350 4 18,MIG MAG WELDING. Flux cored wires,Wires for MIG MAG welding are,usually solid For carbon carbon.
manganese high strength low alloy,steels and stainless steels joint. flux cored wires can be used These,offer the advantages of higher welding. speeds and easier control of fillet,weld profiles,cross section of flux cored wires. Air Products gases for,MIG MAG welding,Ferromaxx Plus is the multi purpose. Air Products welding gases enable the gas for welding carbon carbon. optimum results to be obtained with manganese high strength low alloy. MIG MAG welding of a range of steels and coated steels of all. metals thickness with solid wires in dip spray,and pulse transfer and with metal and.
Pure argon is particularly effective for flux cored wires. welding aluminium and its alloys Also, used for copper and nickel Inomaxx is a range of gases. specially designed for MAG and Pulse, Ferromaxx is a range of selected MAG welding stainless steels. mixtures of argon carbon dioxide and Inomaxx 2 is recommended for. other gases to provide ideal arc welding ferritic and austenitic grades. conditions for spatter free welding of of stainless steel of all thicknesses in. steels Ferromaxx 7 is recommend dip spray and pulse transfer modes. ed for carbon carbon manganese and,high strength low alloy steels up to. 10mm thick in dip spray and pulse,transfer modes Ferromaxx 15 is the. choice for welding carbon carbon, manganese high strength low alloy Faster travel speeds with Ferro.
steels and coated steels in dip spray,maxx Inomaxx and Alumaxx. and pulse transfer modes for all,mean reduced welding costs. Air Products Welder s Handbook,Inomaxx Plus is the choice for. welding all thickness of ferritic and,austenitic stainless steels in dip spray. and pulse transfer and with metal,cored wires,Alumaxx Plus is the high perform.
ance argon helium shielding gas for,MIG welding aluminium and it s alloys. of all thickness in spray and pulse,transfer modes Alumaxx Plus is also. the recommended gas for TIG welding,aluminium and copper. See pages 26 28 for choosing the right,Tungsten inert gas welding. Principles,Tungsten inert gas shielded welding is tungsten.
usually called TIG welding It uses an electrode,arc between a tungsten electrode and. the work to fuse the joint The,electrode is not melted and any filler. metal needed to build up the weld,profile is added separately. Both the molten metal in the weld,pool the tip of the filler wire and the weld pool. hot electrode are protected from,atmospheric contamination by a shield.
of inert gas Usually the gas is argon,but helium by itself or mixed with. argon may be used for special Air Products gases containing. applications Argon hydrogen mix helium give better penetration on. tures can be used for stainless steel metals with high thermal conduc. See page 29,TIG WELDING,Operation Using an arc starting device enables. the arc to be struck without touching,the electrode to the work. TIG welding is suitable for both manual,and mechanised welding. In manual welding the operator points,the electrode in the direction of.
welding and uses the arc to melt the,metal at the joint. If filler metal is required for example,when making a fillet weld it is added. to the leading edge of the weld pool,Filler is supplied as cut lengths of wire. usually 1 metre long,Choice of current, Arc length is controlled by the welder Both direct current dc and. and is usually between 2mm and alternating current ac can be used. 5mm with TIG welding, Heat input to the arc depends on the Direct current with the electrode.
current chosen by the operator connected to the negative terminal. Travel speed is adjusted to match the of the power source is used for. time needed to melt the joint carbon steels,copper and its alloys. stainless steels,nickel and its alloys,titanium and its alloys. zirconium and its alloys,Alternating current is used for. aluminium and its alloys,magnesium and its alloys,aluminium bronze. Air Products Welder s Handbook,Power sources for TIG Crater filling.
Automatic gradual reduction of the,current at the end of a weld run avoids. Power sources for use with TIG,the formation of a crater. welding must be capable of delivering,a constant current at a preset value. welding current,They are often called drooping,characteristic units arc extinguished. Rectifier units are commonly used for,dc welding although motor generators.
may be more suitable for site use time,Single phase transformer units are. almost universally used for welding,aluminium Modern power sources crater. have square waveform end,welding current,Combined ac dc power sources can. be used where there is a mix of work,reduced in,Modern power sources combine steps. constant current and constant voltage,cc cv and are called inverters.
Air Products Welder s Handbook MIG MAG welding principles Gas shielded metal arc welding is a semi automatic process which is suitable for both manual and mechanised operation It is known by a variety of names MIG Metal Inert Gas MAG Metal Active Gas CO2 carbon dioxide A low voltage 18 40V high current 60 500A arc between the end of a wire electrode and the work provides the

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