FAQs – Product Selection

The following frequently asked questions (FAQs) address situations involving product selection.  If you don’t see the question that addresses your concern, we have other FAQs that could assist you.


How is the Lokring fitting superior to welding?

Lokring fittings can be installed without hot work, allowing the fittings to be installed in areas where solvents and other chemicals may be present. Lokring fittings offer “no heat-affected zone” where a weld is susceptible to accelerated corrosion. In addition, Lokring will eliminate weld slag, incomplete fusion, weld suckback, the need for passivation, and x-ray. Some of the other advantages are as follows: schedule improvements, elimination of hot boxes, establishing fire watches, and the need for highly-skilled welders which can be used in other areas such as structural steel, boiler work, and high alloy steels.


Do Lokring products come in Metric sizes?

At this time, Lokring offers only limited metric sizes. Contact your authorized Lokring Distributor for specific applications.
Available material and sizes:
CuNi 90/10
30 and 44.5mm (M30 and M44.5)
6, 10, 12, 14, 15, 16, and 20mm (M06, M10, M12, M14, M15, M16, and M20)
Microalloyed Steel (MAS)
10, 12, 73, and 76.1mm (M10, M12, M73, and M76.1)


Can you make assembled configurations?

Because of our modular method of construction, Lokring can manufacture most piping configurations. Contact your authorized Lokring sales and service representative.


What temperature and pressure will it withstand?

See your Lokring brochure and Lokring fitting specifications for material-specific, size-specific pressure-temperature ratings.

Typical temperature ratings:

  • Microalloyed Steel (MAS): -20 to 650 °F (-28 to 204 °C)
  • 4130 Alloy Steel (LTCS): -20 to 800 °F (-28 to 426 °C) for ASME B31.1
  • 4130 Alloy Steel (LTCS): -50 to 800 °F (-45 to 426 °C) for ASME B31.3
  • Stainless Steel: -20 to 800 °F (-28 to 426 °C) for ASME B31.1
  • Stainless Steel: -425 to 800 °F (-253 to 426 °C) for ASME B31.3
  • 90/10 Copper Nickel: -60 to 425 °F (-51 to 218 °C)
  • 70/30 Copper Nickel: -60 to 425 °F (-51 to 218 °C)
  • Stainless Tube Fittings: -325 to 800 °F (-198 to 428 °C)

Pressures rating vary with size and wall thickness.

Will Lokring Fittings work in process stream applications?

Lokring fittings offer the performance of a welded joint. To date, the bulk of microalloyed steel (MAS) Lokring applications have been on process fluids such as solvents and gases. Lokring microalloyed steel (MAS) fittings are appropriate for typical utility applications. Lokring offers a 4130 Alloy steel for Process applications. This fitting is manufactured from NACE-qualified material and may be suitable for specific hydrocarbon and process applications.


In regards to wall thickness, what is too thin (considering internal corrosion)?

We should not try to answer a question about specific end usage; internal corrosion is the user’s judgment. Most products can be typically used on schedule 10 through schedule 80 (microalloyed steel is not accepted on schedule 10, but may work in certain applications). Lokring MAS fittings have been tested down to the wall of schedule 10.


What piping can Lokring™ fittings be used on?

Microalloyed steel (MAS) fittings are qualified on matching pipe:

  • seamless carbon steel to ASTM A106 (grades A and B) and A53S. It is also qualified on electric resistant welded (ERW) carbon steel to ASTM A53E and A587.
  • 4130 alloy steel (LTCS) fittings are qualified to A333 Gr 6,A106, API 5L and A53 Gr. B.
  • Stainless steel fittings are qualified on matching pipe: Stainless Steel to ASTM A312, type 304/304L/316/316L.
  • CuNi (90/10 Copper Nickel) fittings are qualified on matching pipe: Copper nickel 90/10 class 200 according to Mil-T-16420 250 psig (17 bar) and Copper according to Mil T-24107 to 250 psig (17 bar) with 0.065 inch wall thickness.
  • Stainless steel tube fittings are qualified on matching tube: Stainless steel to ASTM A269 or A213.
  • CuNi (70/30 Copper Nickel) products are qualified on matching tube: Copper nickel 70/30, ¼ inch only with 0.035 and 0.058 inch wall thicknesses.