Aberdeen-based Global Energy Group announced it had acquired A&B Welding Services in a deal that looks likely to have netted a seven-figure sum for its owner Frank Birse.
Global Energy Group said the welding firm was an important addition to the group's service offering, especially for fast-track integrity repairs on offshore production facilities.
These can help oil and gas firms minimise costly downtime on rigs and platforms.
The company said the head of its CPS fabrication operation, Bob Steel, had been eyeing A&B Welding Services for some time.
Led by chairman Roy MacGregor, Global Energy Group expects the acquisition to help CPS maintain rapid growth.
Mr Steel said: "CPS has doubled in size in the past two years, and continues to expand its operations to meet customer demand.
"Earlier this week we closed a separate deal to buy 20,000 square feet of extra facilities, [yesterday's] acquisition further strengthens our capacity and capability. The increased capacity will enable CPS to hire or train an additional 100 people in Aberdeen this year, and we look forward to building on A&B Welding's existing staff in the coming months."
In April, Global Energy Group won a significant vote of confidence from Mitsui. The Japanese giant took a 25% stake in Global Energy Group in exchange for an undisclosed investment in the company, with which it formed an industrial partnership.
At the time Global said the investment by Mitsui and the "industrial partnership" would reinforce its ability to expand organically and through acquisitions in the UK and overseas.
The company said it will work with Mitsui to realise the "huge potential" of the former rig fabrication yard at Nigg on the Cromarty Firth, which it bought last October.
Yesterday a spokesman for the group said it is in talks with oil and gas firms and renewable energy businesses about its plans to develop a multi-sector energy park on the site.
Global Energy Group is refurbishing a rig in the huge dry dock on the site. The most recent accounts filed by A&B Welding Services show the company had net assets of £875,127 at October 31, 2010. The company has 70 employees, compared with around 170 at CPS.
Global Energy Group said Mr Birse and his team will join CPS and the company name will change "in line with the integration".