The pact with United Steel Workers Local 2958 includes a 12-percent general wage increase over the period and a boost in pensions of $300 to $400 a month, said District 3 Director Randy McKay.
The contract covers 514 of Haynes' 750 employees. Haynes makes parts from nickel- and cobalt-based alloys for the aerospace industry and other applications.
McKay said the deal also limits maximum required overtime to 48 hours a month. Some workers had been putting in 12-hour days for seven days a week, McKay said.
Health care benefits increased slightly.
The contract is lucrative at a time many manufacturers are cutting wages and benefits.
McKay said he thinks the generosity was sparked by an initial public offering in March that resulted in the stock skyrocketing to $90 a share, up from $65. A number of Haynes owners became millionaires, he said, and the company seemed willing to spread the wealth.
"Haynes is a good company, and I do think they care about people out here," McKay said.