Shares in the company rose as much as 7.95 pct to their highest since May. They were trading at 1949 pence at 0711 GMT on the London Stock Exchange.
The company, which makes pipes and valves for energy and mining industries, said it had benefited from higher fleet utilisation levels and tightening of production capacity.
Weir Group expects operating margins for its oil and gas unit to be in the low teens through the second half.
"Updated outlook for the group's full-year performance is now for strong constant currency revenue and profit growth," the company said in a statement.
(Reporting by Sanjeeban Sarkar in Bengaluru; Editing by Gopakumar Warrier)