Cast Iron Plugs | McMaster-Carr

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Pipe Size

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Pressure Class

125

300

Maximum Pressure @ Temperature

For Use With

Flange Material

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Length

For Flange Class

Specifications Met

Maximum Steam Pressure @ Temperature

125 psi @ 350° F

300 psi @ 550° F

DFARS Specialty Metals

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Export Control Classification Number (ECCN)

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Weight

19 Products

How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

Medium-Pressure Iron and Steel Threaded Pipe Fittings

With better strength than our low-pressure iron and steel pipe fittings, these can handle medium-pressure applications. They are for use in noncorrosive environments.

For technical drawings and 3-D models, click on a part number.

Plugs with External Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class : 300
Specifications Met: See Table
Pipe Nipples and Pipe: Use Schedule 80 steel
Flanges: Use Class 300 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material	Specifications Met		Each
1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
3/4	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	0000
1	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	0000
1 1/4	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
1 1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
2 1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000

Low-Pressure Iron and Steel Threaded Pipe Fittings

Use these fittings for low-pressure applications in noncorrosive environments.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Presure Class:
Steel: 150
Iron: 125
Pipe Nipples and Pipe: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
2 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000
3	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000

Plugs with External Square Drive

For Use With:
NPT and BSPT: Air, Natural Gas, Oil, Steam, Water
NPTF: Air, Natural Gas, Steam, Water
Pressure Class:
NPT Iron: 125
BSPT Iron: 150
Specifications Met:
See table
Pipe Nipples and Pipe:
NPT and BPST: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
2 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000
3	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000

Low-Pressure Galvanized Iron and Steel Threaded Pipe Fittings

The galvanized finish on these fittings provides fair corrosion resistance. Fittings are for use in low-pressure applications.

For technical drawings and 3-D models, click on a part number.

Plugs with External Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: See table
Specifications Met:
NPT Steel: SAE J531
NPT Iron: ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed
BSPT: ASTM A197, DIN EN 10226
Pipe Nipples and Pipe: Use Schedule 40 steel
Flanges: Use Class 150 galvanized steel

NPT Male
Pipe Size	Plug Construction	Pressure Class	Max. Pressure	Max. Steam Pressure	Material		Each
2 1/2	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000
3	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	00000
3 1/2	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000
4	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000