A hammer union is a type of fitting used in the oil and gas industry to connect two pieces of pipe or tubing together. It is a threaded, mechanical, and sealing connection that is commonly used in drilling, completion, and production operations.

Hammer unions are designed to provide a reliable and quick way to make and break connections between pipes or tubing, which is essential in drilling and workover operations where equipment needs to be regularly moved and repositioned. The union consists of four parts: two female ends that are threaded to connect to the pipe or tubing, and two male ends that are threaded and tapered to fit inside the female ends.

The male and female ends of the hammer union are pressed together by a hammer-like action, hence the name “hammer union.” A locking nut is then tightened onto the threaded ends to ensure a secure and leak-proof connection.

Hammer unions come in a range of sizes and pressure ratings, from small 1-inch unions for low-pressure applications to large 10-inch unions for high-pressure operations. They are typically made from carbon steel or stainless steel and can be equipped with different sealing materials, such as Buna-N or Viton, to ensure compatibility with various types of fluids and gases.