HELSINKI (Reuters) -Finland’s Outokumpu on Thursday posted stronger-than-expected core earnings for the second quarter despite a slight decrease in sales volumes as steel prices rose following Russia’s invasion of Ukraine. “The market environment has been exceptionally favourable, but we have now started to see softening especially on the commodity business,” Chief Executive Heikki Malinen said in a statement. Stainless steel deliveries decreased by 4% year on year to 603,000 tonnes, below a mean estimate of 643,000 tonnes. For the ongoing third quarter Outokumpu expects stainless steel delive…