What Are Hammer Lug Unions

Hammer lug unions enable fast connections in piping and hose assemblies that can hold up against harsh conditions. By utilizing a simple hammer, technicians can efficiently install these fittings for the oil and gas, chemical, and construction industries.

HART Industrial Unions, LLC manufactures durable hammer lug unions for connecting such assemblies, as well as other union types to fit your needs. Typically, our hammer nuts are manufactured from 303 stainless steel, but are also available in carbon steel or Hastelloy C276 upon request.
HART hammer nuts are interchangeable with standard HART union nuts, and can also be manufactured with ACME style threads upon request. Hammer lug unions are particularly well suited to high-pressure applications.

Hart Industrial O-Ring Unions are engineered to provide a minimum 3000 lb. service and are the most popular union in the industry for general purpose applications. The flat face design provides turbulence free fit across seats. This design is ideal where piping requirements dictate the necessity of having a flat face seal to make and break the pipeline. All HART Unions are made in the USA.

HART O-Ring Union Features:

  • Turbulence Free: All unions provide a turbulence-free fit across the seats
  • O-Ring Isolation: The O-Ring seal is strategically located in the thread
    piece face eliminating O-Ring media contact and added protection against abrasives and erosion. A variety of O-Rings for any application are available.
  • Precision Machined Components: All unions are precision machined to provide high quality and fail-safe leak proof reliability.
  • Interchangeable End Connections: HART’s male threaded connections feature interchangeable configurations with other threaded or welded connections, reducing the need for nipples or additional fittings.
  • Material Versatility: Unions can be provided in all standard metals or combinations of metals. This includes 304 Stainless, 316 Stainless, A105 Carbon Steel, Brass, Monel 400, Hastelloy, and Titanium.
  • Excellent Vibration Resistance: Seals will not loosen, even under extreme pressure and pressure surges.
  • No Maintenance: Once the initial seal is made, no further tightening is required.
  • Specifications

  • 3D Animations
  • Datasheets

    HART Hammer Nut Specifications.pdf

    HART H-3131 Series Hammer Nut Assembly

    HART H-3131 Series Hammer Nut Assembly.pdf

A wide range of industries and applications use hammer lug unions, including:

  • Chemical facilities
  • Hose assemblies and pipelines in the oil and gas industry
  • Marine dredging
  • Onshore and offshore drilling rigs for transferring gas, petroleum, sand slurry, steam, water, etc.
  • Mining
  • Trucking and railway applications
  • Water flood pipelines

The reliable construction and ease of installation are what make hammer lug unions so popular across these and other industrial applications.

At HART Industrial Unions, we engineer our hammer lug unions to provide a minimum 3,000-lb. service, and they are among the most popular unions in general purpose applications. For jobs requiring a flat-face seal to connect and disconnect piping, we use a flat-face design that allows for a turbulence-free fit across seats. We also deep counter-bore our sockets for ideal alignment at the end of piping. At HART Industrial Unions, schedule 40 and 80 sizes come standard, but we have the capability to custom design additional schedule sizes to meet your needs.

In addition to hammer lug unions, we can supply a variety of other Sure Seal O-ring union types. Our manufacturing capabilities enable us to produce custom unions for your application, including female and male threaded unions, socketweld unions, buttweld unions, orifice unions, and dielectric insulated unions, among others. We will work with you to understand your unique specifications and design a product that is right for you.

To learn more about our Engineering and Manufacturing Capabilities, visit our CAPABILITIES

If you would like to request more information about our parts and get started on finding the right solution, Contact us today.