weldabilty of metals and factors affecting weldability.

WELDABILITY MEANING


In simple weld-ability is the ability of material to be welded or join-ability of material.

weldeability means,weldeability of metals,weldeable metals,testings for checking weldeability,alloying elements and their effects on weldeability


Weldability Encompasses

  • Metallurgical compatibility
         it implies fusion ability of parent metal and weld metal.

  • weld metals ability to be welded with mechanical soundness.
  • service ability of resulted weld joint.

COMMONLY WELDABLE BASE METALS

  • FERROUS

  1. STAINLESS STEEL
  2. CAST STEELS
  3. ALLOY STEELS
  4. CAST IRONCARBON STEELS
  5. HSLA,HSS,etc

  • NON FERROUS

  1. ALUMINIUM AND ITS ALLOYS.
  2. COPPER AND ITS ALLOYS
  3. MAGNESIUM AND ITS ALLOYS.
  4. ZINK AND ITS ALLOYS
  5. NICKEL AND ITS ALLOYS

WELDABILITY TESTINGS

  • THEORETICAL TESTS

  • SIMULATED TEST

  • ACTUAL WELDING TESTS

  • a)fabrication weldability test- hot cracking test,root cracking test,hydrogen induced cracking test.
  • b)Service weldability tests- tensile,hardness and bend test, impact test, corrosion test, fatigue test, creep test etc etc.

ALLOYING ELEMENTS AND THEIR EFFECTS ON WELDABILITY

  • HARDENABILITY
alloying elements decreases or increases the hardenability of heat affected zone.
Elements which have highest effect on hardenability are-  C,Mn,Mo,Cr,V,Ni and Si.

  • FORM AGE HARDENING PRECIPITATES
  • ALLOYING ELEMENTS GIVES GRAIN REFINEMENT
  • SEGREGATION IS REDUCED
  • STRENGTHEN THE METAL
  • INCREASE MECHANICAL PROPERTIES
  • FORM CARBIDES
  • CONTROLS THE DUCTILE TO BRITTLE TRANSFORMATION
  • PROVIDES DE-OXIDATION

FACTORS AFFECTING WELDABILITY

  • Thermal conductivity
material with high thermal conductivity(K) is treated as difficult to be welded.
  • Melting point
materials having medium melting point can be welded easily
  • Electrical resistance
metal having very high electrical resistance is difficult to weld because it requires high heat energy.
  • Reactivity
if metal reacts with air,water or surrounding it becomes hard to weld.
  • Surface conditions
this is also very important term.clean surface gives good weld finish and strength and dirty surface is difficult to weld it creates porosity,pin holes and creates bad weld finish.

tags
weldability concept,meaning,defination,factors affecting weldability,alloying elements and their effects on weldability,weldability testing methods,commonly weldeable base parent metals and alloys,Fabrication Engineers, Metallurgy Engineers, Welding Engineers, Mechanical Engineers,

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