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June 3 (Reuters) - Applied Aerospace & Defense AADX.N achieved a valuation of $3.54 billion after its shares opened 3.8% above the offer price in their New York Stock Exchange debut on Wednesday, setting the tone for a busy week of initial public offerings.

The stock opened at $20.75 apiece, compared with the offer price of $20. The Huntsville, Alabama-based space and defense hardware provider raised $650 million in the IPO by selling 32.5 million shares within the marketed range of $18 to $21 ​apiece.

Seven companies spanning AI infrastructure to software are slated to go public in New York this week, tying the record for the busiest week since 2021, according to Renaissance Capital, a provider of IPO-focused research and ETFs.

Defense tech has also been a recurring theme in the IPO market since April as issuers look to capitalize on structural tailwind stemming from the Middle East conflict.

Middle-market-focused buyout firm Greenbriar Equity Group combined portfolio companies Applied Aerospace and PCX Aerosystems last year to form Applied Aerospace & Defense.

Applied, whose legacy businesses have been operating for more than a century, makes complex hardware such as solid rocket motor cases, flight control surfaces, fuselage assemblies, and engine shafts, for aerospace and defense markets.

The company has expanded through more than a dozen acquisitions since 2021. Business from Applied's top three customers accounted for roughly 59% of its revenue last year.

It has long-standing supplier relationships with blue-chip firms SpaceX, Boeing BA.N, Northrop NOC.N, RTX RTX.N, Lockheed LMT.N and Blue Origin.

The firm supplies vital components such as nose cones, fairings, protective covers, and payload adapters for SpaceX's Falcon 9 rocket.