Filter plate shade numbers for arc welding are
selected based on

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Apressure vessel with an r/t 20 cannot be treated as thin walled vessel. a)-trune b)- false

Precipitation hardening can be achieved in many light alloys by a three-step heat treatment. what is carried out and what is the purpose at each step? why is such a treatment necessary based on the nucleation and growth theory of phase transformation. compare this treatment with tempering martensite for carbon steels (similarities and differences).