What is MSS SP-79 standard?

Ratings, tolerances, finish, dimensions, marking, and material specifications for socket-welding reducer inserts used with ASME B16.11 are covered by the mss sp-79 standard practice.

Socket-welding fittings of classes 3000 and 6000. SI (metric) measurements and conventional unit dimensions are used for these reducer inserts. Essential measures, finish, tolerances, testing, labeling, and material are covered by Mss-sp-79-2009 reducer inserts.

MSS SP-79 Technical Information

Applicable for Reducer Insert, Socket weld fittings (Type 1 & Type 2)
Class 3000 & 6000
NPS Size 1/4, 3/8, 1/2, 3/4, 1, 1 1/4, 1 1/2, 2, 2 1/2, 3, 4
DN Size 8, 101, 15, 20, 25, 32, 40, 50, 65, 80, 100,
Material Stainless, Carbon, Alloy, Titanium, Nickel Alloy, All ferrous & non ferrous metals
How to buy? Contact listed verified MSS SP-79 fittings suppliers in UAE for best quote

And minimum strength specifications for threaded, socket-welded, and 90-degree integrally reinforced forged branch outlet fittings. Forged branch outlet fittings with integral reinforcement have socket welding, threaded, and buttwelding ends.

The only organization in the world devoted to the technical requirements of the valve and fittings business is MSS (Manufacturers Standardization Society).

Twenty-five technical committees write and update standards and norms that include subjects including valves, valve actuators, pipe fittings, flanges, and pipe hangers.

Steels that have been entirely killed must have been produced using an open hearth, basic oxygen, or electric furnace method to be the raw material for MSS SP 75 pipe fittings. Blooms, billets, slabs, forging-quality bars, plates, seamless or fusion-welded pipes, and more make up this material.

Pipe fittings made to MSS SP 75 specifications must be delivered in their heat-treated state. The fitting’s welding ends (bevels) must be provided with varied wall thicknesses.

Mss sp 79 specification

Mss sp 79 reducer inserts dimensions

MSS SP-79 standard defines manufacturing standards for socket welding reducer inserts such as dimensions, ratings, finish, tolerances, material, and marking requirements

What finishes, tolerances, testing specified for reducing insert mss sp 79?

This MSS Standard Practice was created with the approval of the MSS Coordinating Committee and MSS Technical Committee 105, Forged Steel Fittings.

This Standard Practice’s content results from the efforts of knowledgeable and skilled volunteers who wanted to create a practical, understandable, and inclusive standard that would help the whole industry.

The maker, the user, and the general public are all expected to follow this Mss sp-79 standard, which outlines the minimum requirements.


Surfaces must be smooth and have a workmanship-like finish, devoid of sharp burrs.


Proof Testing This Standard Practice does not require testing for fittings constructed of standard materials.

For use with ASME B16.11, Class 3000 and 6000 socket-welding fittings, MSS SP-79 covers ratings, dimensions, tolerances, finish, marking, and material requirements.

Most of the time, small-size pipes and piping systems use socket weld pipe fittings. As per ASME B16.11 and other dimensional standards, solid steel is first forged, then heated, before being machined to create socket weld pipe fittings.

MSS SP-79 standard applies on Class 3000 and 6000 reducing insert in different materials

Which are the materials which comes under MSS SP 79 socket weld reducing insert manufacturing specification?

A pipe attachment detail is a socket weld fitting. In this scenario, the pipe will be put into a recess in a pipe, fitting, valve, or flange. Seal welds of the filet kind will be used to connect the pipes or valves to the other pipe sections.

So, Socket weld reducing insert – mss sp-79 is a good option in some situations. This is because while constructing your pipeline project, the advantages of solid structural strength and excellent leakage integrity will be crucial considerations.

Materials including stainless steel, duplex and super duplex steel, nickel alloy, copper alloy, carbon steel, alloy steel, Hastelloy, Monel, Inconel, titanium, Inconel, alloy 20, 254 SMO, mild steel (MS), and brass are used to make forged socket weld reducer inserts.

Socket Weld Reducing Insert Type 1 and Type 2 are the two primary varieties offered.

They serve as pipe connectors and help to enlarge the diameter. The production of Socket Weld Reducer Inserts follows MSS SP-79. They make it possible to quickly and affordably combine pipeline reductions using joint Socket Weld fittings.