Oilfield services firm National Oilwell Varco Inc. (NOV) has agreed to acquire industrial parts maker Ameron International Corp. (AMN) for about $772 million in cash. The transaction, which has been approved by the boards of both the companies but awaits regulatory and shareholder approvals, is expected to close by the fourth quarter of 2011. As [...] (NOV) National Oilwell Varco Buying Ameron International