Valmec and Altrad Australia have entered into a binding scheme implementation under which Altrad will pay 41.3c per share for 98% of Valmec's shares.
The cash bid price represents a 29.1% premium to Valmec's last closing price.
The Valmec board is unanimously backing the deal with statements of intention received by Altrad for two further shareholders, representing 18.8% of Valmec.
Valmec provides design, construction, operations and maintenance services to the mining, energy and infrastructure sectors.
Valmec chairman Stephen Zurhaar said the transaction was compelling and urged shareholders to support it.
"This provides a great opportunity for shareholders to realise value at a significant premium to the prevailing market price," he said.
"The quality of this offer is further strengthened in that it comprises 100% cash consideration as opposed to both cash and scrip components which is often the case in transactions of this nature."
Altrad is a global leader in industrial maintenance services, employing about 36,000 people globally, including 1000 in Australia.
Australia and the Asia-Pacific have been identified as a growth region for Altrad.
"The acquisition of Valmec will mark another transformational milestone for our Asia-Pacific business and deliver a value-accretive step change in the scale and diversity for our company," Altrad Services CEO, Asia Pacific Neil Sadler said.
"Once the scheme is implemented, I look forward to working with my leadership team and the Valmec team to identify value-adding opportunities for our combined existing and prospective client bases."
Valmec shareholders will be asked to vote on the deal in October.
Valmec was advised by Azure Capital and Dentons, while Altrad was advised by Longreach Capital and Squire Patton Boggs.
Shares in Valmec jumped 25% to 40c.