Cast Iron Plugs | McMaster-Carr

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19 Products

About Pipe and Fittings

Measure your pipe and fittings to identify their pipe size, thread size, schedule, and thread type. Then, find compatible components.

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.

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	4627K333	00000
3/4	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	4627K334	0000
1	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	4627K335	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	4627K336	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	4627K337	00000
2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	4627K338	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	4627K416	00000

Low-Pressure Iron and Steel Threaded Pipe Fittings

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

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	44605K705	000000
3	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K706	00000
3 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K707	00000
4	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K708	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	44605K701	000000
3	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K702	00000
3 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K703	00000
4	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	44605K704	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.

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	4638K934	000000
3	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	4638K935	00000
3 1/2	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	4638K936	00000
4	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	4638K939	000000