STUDYING THE IMPROVEMENT OF TENSILE STRENGTH OF LOW ALLOY HIGH STRENGTH STEEL WELDS USING AN ECONOMICAL TECHNIQUE

Abstract

Low alloy steels are particularly used in manufacturing several parts in the heavy
engineering industries, agricultural equipment and dies which may be subject to service
failure, and thus may need to be repaired by one of the welding processes. The weldability
of steels is determined by their sensitivity to cracks that can be prevented by the use of
special welding procedures which are often expensive and difficult to use. Manual metal arc
welding of low alloy high strength steels was done firstly, using a cheap electrode (OK
46.00), followed by the use of an economical technique which depends on coiling copper
wires with different diameters around the cheap electrode. The expensive electrode (OK
73.68) was also used for comparison. Results showed an increase in the tensile strength (712
MPa) and weld joint efficiency (83.8%) when the expensive iron powder low hydrogen
covering electrode (OK 73.68) was used. On the other hand, the tensile strength was
decreased to (206 MPa) and the weld joint efficiency to (24.2%) when the cheap electrode
(OK 46.00) was used. Coiling a (0.6 mm) dia. copper wire around the (OK 46.00) electrode
increased the tensile strength and weld joint efficiency to (510 MPa) and (60%) respectively.