Stainless Steel Threaded Fittings

Stainless Steel Threaded Plugs and Caps

A stainless plug closes the open end of a stainless line or equipment and is made of AISI 304. The male plug screws into a female port, while the female cap screws onto a male pipe end.

It is used on unused process tank ports, sampling points, line ends during testing and outlets to be extended later. Plugs and caps are supplied in 12 sizes each from 1/8″ to 4″.

2 typesmale plug, female cap

1/8″ – 4″size range (product range)

24 sizes12 plugs + 12 caps

20 barat −20 … +38 °C (ISO 4144)

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Main Applications

Unused ports on process tanks and reactors
Closing sampling and measuring points
Line ends during pressure testing
Spare outlets on manifolds
Drain and air release ports
Closing after cleaning in food lines

Technical Data

Fitting types	Male plug; female cap
Product standard	ISO 4144 (manufacturer sheet)
Material	AISI 304 stainless steel (product range)
Thread (plug)	ISO 7-1 R taper male thread
Thread (cap)	ISO 7-1 Rp female thread
Plug sizes	1/8″, 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″, 3″, 4″ (product range)
Cap sizes	1/8″, 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″, 3″, 4″ (product range)
Pressure, −20 … +38 °C	20 bar (ISO 4144 Table 2, manufacturer sheet)
Pressure, 100 °C	16.5 bar (ISO 4144 Table 2, manufacturer sheet)
Pressure, 150 °C	15 bar (ISO 4144 Table 2, manufacturer sheet)
Plug head	Hexagonal or square, depending on model
Surface	Stainless, uncoated

Material Options

Part	AISI 304 stainless	AISI 316 stainless	Galvanized malleable iron
Body	AISI 304, cast or bar depending on model	AISI 316, depending on model	Malleable iron EN-GJMB-350-10, galvanized
Surface	Uncoated stainless	Uncoated stainless	Zinc coated
Thread	Plug R male, cap Rp female	Plug R male, cap Rp female	Plug R male
Pressure rating	20 bar −20…+38 °C (ISO 4144)	20 bar −20…+38 °C (ISO 4144)	25 bar −20…120 °C (EN 10242)
Suitable media	Food, drinking water, mild chemicals	Chloride-containing water, seawater, aggressive chemicals	Cold domestic water, fire water

Which material? A closed end is in constant contact with the medium, which often stagnates; 316 plugs or caps should be preferred in chloride and aggressive environments.

Advantages

A Solution for Every End

Plug for female ports, cap for male ends

Complete Size Set

12 sizes each from 1/8″ to 4″

Hygienic Closure

The uncoated surface is cleanable

Reusable

Can be removed and refitted

Construction and Design Features

Plug with R taper male thread and wrench head
Cap with Rp female thread and closed bottom
Stainless body, uncoated
ISO 4144 pressure ratings

Send whether the end to be closed is female or male threaded, its size and quantity; we will confirm the suitable stainless plug or cap from stock.

How to Choose?

Determine the end typeChoose a plug for a female port and a cap for a male pipe end.
Measure the sizeDetermine the thread size of the port or pipe end in inches.
Choose the gradePrefer 316 with stagnant and chloride-containing media.
Plan the thread sealingOn ends removed often, use a tape or sealant that eases removal.