Question

CE-331: A steel floor girder in an existing building needs strengthening by welding a steel member to its bottom flange. The steel grade is unknown, but materials testing has revealed the following percentages by weight of the following alloy chemical elements in the girder: C = 0.17%; Cu = 0.21%; Mn = 0.9%; Cr = 0.11%; Mo = 0.25%; Ni = 0.23%; Cd = 0.11% V = 0.09%; Si = 0.25%; and Zn = 0.05%. Determine the weldability of this steel girder.

Answer 1

Ans) To determine Weldability of steel girder first find carbon equivalent (CE) by using Dearden and O'Neil formula ,

CE = % C + (%Mn/6) + (%Cr + %Mo + %V) / 5 + (%Cu + %Ni) /15

Putting given values,

=> CE = 0.17 + (0.9/6) + (0.11 + 0.25 + 0.09) / 5 + (0.21 + 0.23)/15

=> CE = 0.17 + 0.15 + 0.09 + 0.029 = 0.439

Weldability based on CE can be shown as :     

Carbon Equivalent (CE)	Weldability
Less than 0.35	Excellent
0.36 - 0.40	Very Good
0.41 - 0.45	Good
0.46 - 0.50	Fair
More than 0.50	Poor

Since , CE = 0.41 < 0.439 < 0.45 , Weldability of this steel girder is good