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    89 Products
    About Pipe and Fittings
    industrial info icon

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

    Low-Pressure Aluminum Unthreaded Pipe Flanges

    Also known as Pressure Class 125 flanges, these are for use in low-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. Flanges are aluminum, which is lightweight with good corrosion resistance.
    Flanges
    Image of Product. Front. Front orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Flanges, Butt Weld, Flat Surface.
    Image of Product. Flat Surface on Back. Back orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Flanges, Butt Weld, Flat Surface.

    Front

    Flat Surface

    on Back

    Butt-Weld Fitting Connection—Butt-weld flanges are also known as weld-neck flanges; the flange neck has a beveled end that, when flush to pipe, creates a trough for a strong weld.
    Slip-on-Weld Fitting Connection—Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.
    Pipe
    Size
    Bolt
    Hole
    (A)
    (B)
    Flanged Connection
    Surface (B)
    Flange
    OD
    For Bolt
    Dia.
    Dia.
    No.
    Of
    Bolt Circle
    Dia.
    Pressure
    Class
    Material
    Max. Pressure
    @ Temp.
    Each
    Butt Weld
    1/2
    		1/2
    		Flat3 1/2"1/2"5/8"42 3/8"125
    		356 Aluminum150 psi @ 72° F44705K543000000
    3/4
    		3/4
    		Flat3 7/8"1/2"5/8"42 3/4"125
    		356 Aluminum150 psi @ 72° F44705K54400000
    1
    		1
    		Flat4 1/4"1/2"5/8"43 1/8"125
    		356 Aluminum150 psi @ 72° F44705K54500000
    1 1/2
    		1 1/2
    		Flat5"1/2"5/8"43 7/8"125
    		356 Aluminum150 psi @ 72° F44705K547000000
    2
    		2
    		Flat6"5/8"3/4"44 3/4"125
    		356 Aluminum150 psi @ 72° F44705K548000000
    2 1/2
    		2 1/2
    		Flat7"5/8"3/4"45 1/2"125
    		356 Aluminum150 psi @ 72° F44705K549000000
    3
    		3
    		Flat7 1/2"5/8"3/4"46"125
    		356 Aluminum150 psi @ 72° F44705K551000000
    4
    		4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K552000000
    6
    		6
    		Flat11"3/4"7/8"89 1/2"125
    		356 Aluminum150 psi @ 72° F44705K553000000
     
    Slip-On Weld Female
    1/2
    		1/2
    		Flat3 1/2"1/2"5/8"42 3/8"125
    		356 Aluminum150 psi @ 72° F44705K3700000
    3/4
    		3/4
    		Flat3 7/8"1/2"5/8"42 3/4"125
    		356 Aluminum150 psi @ 72° F44705K3800000
    1
    		1
    		Flat4 1/4"1/2"5/8"43 1/8"125
    		356 Aluminum150 psi @ 72° F44705K36100000
    1 1/4
    		1 1/4
    		Flat4 5/8"1/2"5/8"43 1/2"125
    		356 Aluminum150 psi @ 72° F44705K36200000
    1 1/2
    		1 1/2
    		Flat5"1/2"5/8"43 7/8"125
    		356 Aluminum150 psi @ 72° F44705K36300000
    2
    		2
    		Flat6"5/8"3/4"44 3/4"125
    		356 Aluminum150 psi @ 72° F44705K36400000
    2 1/2
    		2 1/2
    		Flat7"5/8"3/4"45 1/2"125
    		356 Aluminum150 psi @ 72° F44705K36500000
    3
    		3
    		Flat7 1/2"5/8"3/4"46"125
    		356 Aluminum150 psi @ 72° F44705K36600000
    4
    		4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K367000000
    6
    		6
    		Flat11"3/4"7/8"89 1/2"125
    		356 Aluminum150 psi @ 72° F44705K542000000
    8
    		8
    		Flat13 1/2"3/4"7/8"811 3/4"125
    		356 Aluminum150 psi @ 72° F44705K772000000
     
    Reducing Flanges
    Image of ProductInUse. Slip-On Weld. Side1 orientation. Contains Annotated. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Reducing Flanges, Slip-On Weld Female, Flat Surface.
    Image of Product. Front. Front orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Reducing Flanges, Slip-On Weld Female, Flat Surface.
    Image of Product. Flat Surface on Back. Back orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Reducing Flanges, Slip-On Weld Female, Flat Surface.

    Slip-On Weld

    Front

    Flat Surface

    on Back

    Reducing flanges allow you to transition your system to a smaller pipe size; attach to a flange with a larger pipe size but with the same flange dimensions.
    Slip-on-Weld Fitting Connection—Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.
    Bolt
    Hole
    Pipe Size
    (A)
    For Flange
    Pipe Size (B)
    Flanged Connection
    Surface (B)
    Flange
    OD
    For Bolt
    Dia.
    Dia.
    No.
    Of
    Bolt Circle
    Dia.
    Pressure
    Class
    Material
    Max. Pressure
    @ Temp.
    Each
    Slip-On Weld Female
    3
    		4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K7680000000
    6
    		8
    		Flat13 1/2"3/4"7/8"811 3/4"125
    		356 Aluminum150 psi @ 72° F44705K771000000
     
    Blind Flanges
    Image of Product. Front. Front orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Blind Flanges, Flanged, Flat.
    Image of Product. Flat Surface on Back. Back orientation. Pipe and Fittings. Low-Pressure Aluminum Unthreaded Pipe Flanges, Blind Flanges, Flanged, Flat.

    Front

    Flat Surface

    on Back

    Bolt
    Hole
    Pipe
    Size
    Flanged Connection
    Surface
    Flange
    OD
    For Bolt
    Dia.
    Dia.
    No.
    Of
    Bolt Circle
    Dia.
    Pressure
    Class
    Material
    Max. Pressure
    @ Temp.
    Each
    Flanged
    1/2
    		Flat3 1/2"1/2"5/8"42 3/8"125
    		356 Aluminum150 psi @ 72° F44705K531000000
    3/4
    		Flat3 7/8"1/2"5/8"42 3/4"125
    		356 Aluminum150 psi @ 72° F44705K53200000
    1
    		Flat4 1/4"1/2"5/8"43 1/8"125
    		356 Aluminum150 psi @ 72° F44705K53300000
    1 1/4
    		Flat4 5/8"1/2"5/8"43 1/2"125
    		356 Aluminum150 psi @ 72° F44705K53400000
    1 1/2
    		Flat5"1/2"5/8"43 7/8"125
    		356 Aluminum150 psi @ 72° F44705K53500000
    2
    		Flat6"5/8"3/4"44 3/4"125
    		356 Aluminum150 psi @ 72° F44705K53600000
    2 1/2
    		Flat7"5/8"3/4"45 1/2"125
    		356 Aluminum150 psi @ 72° F44705K53700000
    3
    		Flat7 1/2"5/8"3/4"46"125
    		356 Aluminum150 psi @ 72° F44705K538000000
    4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K539000000
    6
    		Flat11"3/4"7/8"89 1/2"125
    		356 Aluminum150 psi @ 72° F44705K541000000
    8
    		Flat13 1/2"3/4"7/8"811 3/4"125
    		356 Aluminum150 psi @ 72° F44705K399000000
     

    Low-Pressure Aluminum Threaded Pipe Flanges

    Also known as Pressure Class 125 flanges, these are for use in low-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. Flanges are aluminum, which is lightweight with good corrosion resistance.
    Flanges
    Image of Product. Front. Front orientation. Pipe and Fittings. Low-Pressure Aluminum Threaded Pipe Flanges, Flanges, Flanged Fitting Connection, Female, Threaded Fitting Connection, Flat Surface.
    Image of Product. Flat Surface on Back. Back orientation. Pipe and Fittings. Low-Pressure Aluminum Threaded Pipe Flanges, Flanges, Flanged Fitting Connection, Female, Threaded Fitting Connection, Flat Surface.

    Front

    Flat Surface

    on Back

    Pipe
    Size
    Bolt
    Hole
    (A)
    (B)
    Flanged Connection
    Surface (B)
    Flange
    OD
    For Bolt
    Dia.
    Dia.
    No.
    Of
    Bolt Circle
    Dia.
    Pressure
    Class
    Material
    Max. Pressure
    @ Temp.
    Each
    NPT Female
    1/2
    		1/2
    		Flat3 1/2"1/2"5/8"42 3/8"125
    		356 Aluminum150 psi @ 72° F44705K228000000
    3/4
    		3/4
    		Flat3 7/8"1/2"5/8"42 3/4"125
    		356 Aluminum150 psi @ 72° F44705K22900000
    1
    		1
    		Flat4 1/4"1/2"5/8"43 1/8"125
    		356 Aluminum150 psi @ 72° F44705K23100000
    1 1/4
    		1 1/4
    		Flat4 5/8"1/2"5/8"43 1/2"125
    		356 Aluminum150 psi @ 72° F44705K23200000
    1 1/2
    		1 1/2
    		Flat5"1/2"5/8"43 7/8"125
    		356 Aluminum150 psi @ 72° F44705K23300000
    2
    		2
    		Flat6"5/8"3/4"44 3/4"125
    		356 Aluminum150 psi @ 72° F44705K23400000
    2 1/2
    		2 1/2
    		Flat7"5/8"3/4"45 1/2"125
    		356 Aluminum150 psi @ 72° F44705K23500000
    3
    		3
    		Flat7 1/2"5/8"3/4"46"125
    		356 Aluminum150 psi @ 72° F44705K23600000
    4
    		4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K238000000
    6
    		6
    		Flat11"3/4"7/8"89 1/2"125
    		356 Aluminum150 psi @ 72° F44705K437000000
    8
    		8
    		Flat13 1/2"3/4"7/8"811 3/4"125
    		356 Aluminum150 psi @ 72° F44705K745000000
     
    Reducing Flanges
    Image of Product. Front. Front orientation. Pipe and Fittings. Low-Pressure Aluminum Threaded Pipe Flanges, Reducing Flanges, Flanged Fitting Connection, Female, Threaded Fitting Connection, Flat Surface.
    Image of Product. Flat Surface on Back. Back orientation. Pipe and Fittings. Low-Pressure Aluminum Threaded Pipe Flanges, Reducing Flanges, Flanged Fitting Connection, Female, Threaded Fitting Connection, Flat Surface.

    Front

    Flat Surface

    on Back

    Reducing flanges allow you to transition your system to a smaller pipe size; attach to a flange with a larger pipe size but with the same flange dimensions.
    Bolt
    Hole
    Pipe Size
    (A)
    For Flange
    Pipe Size (B)
    Flanged Connection
    Surface (B)
    Flange
    OD
    For Bolt
    Dia.
    Dia.
    No.
    Of
    Bolt Circle
    Dia.
    Pressure
    Class
    Material
    Max. Pressure
    @ Temp.
    Each
    NPT Female
    1/2
    		3/4
    		Flat3 7/8"1/2"5/8"42 3/4"125
    		356 Aluminum150 psi @ 72° F44705K712000000
    3/4
    		1
    		Flat4 1/4"1/2"5/8"43 1/8"125
    		356 Aluminum150 psi @ 72° F44705K71500000
    1
    		1 1/4
    		Flat4 5/8"1/2"5/8"43 1/2"125
    		356 Aluminum150 psi @ 72° F44705K71800000
    1 1/4
    		1 1/2
    		Flat5"1/2"5/8"43 7/8"125
    		356 Aluminum150 psi @ 72° F44705K72100000
    1 1/2
    		2
    		Flat6"5/8"3/4"44 3/4"125
    		356 Aluminum150 psi @ 72° F44705K72400000
    2
    		2 1/2
    		Flat7"5/8"3/4"45 1/2"125
    		356 Aluminum150 psi @ 72° F44705K72700000
    2
    		3
    		Flat7 1/2"5/8"3/4"46"125
    		356 Aluminum150 psi @ 72° F44705K733000000
    3
    		4
    		Flat9"5/8"3/4"87 1/2"125
    		356 Aluminum150 psi @ 72° F44705K736000000
    4
    		6
    		Flat11"3/4"7/8"89 1/2"125
    		356 Aluminum150 psi @ 72° F44705K739000000
    6
    		8
    		Flat13 1/2"3/4"7/8"811 3/4"125
    		356 Aluminum150 psi @ 72° F44705K742000000
     

    Stainless Steel Hex Head Screw Kits for Metal Pipe Flanges

    Image of ProductInUse. Shown Installed. Front orientation. Hex Head Screws. Stainless Steel Hex Head Screw Kits for Metal Pipe Flanges.
    Image of Product. Front orientation. Hex Head Screws. Stainless Steel Hex Head Screw Kits for Metal Pipe Flanges.

    Shown Installed

    Join aluminum or stainless steel pipe flanges. These kits come with corrosion-resistant screws and nuts in the right size and number to match your flange's bolt holes. The screws have a head with six flat sides to keep wrenches and sockets from slipping and rounding off the drive.
    Screw length is measured from under the head. For a tight seal, you’ll also need a gasket between the flanges.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these screws won't rust. However, they don't hold up to the harsh chemicals that 316 stainless steel screws can.
    316 Stainless Steel—Superior to 18-8 stainless steel screws, these won't degrade when exposed to harsh weather, salt water, and most chemicals.
    PTFE-Coated 316 Stainless Steel—A slippery coating prevents these nuts from binding or sticking during installation. They resist rust in wet and outdoor environments and can handle occasional exposure to mild acids and chemicals without corroding.
    Screw
    Nut
    18-8 Stainless Steel
    Screws and Nuts
    316 Stainless Steel
    Screws and Nuts
    316 Stainless Steel Screws and Blue
    PTFE-Coated 316 Stainless Steel Nuts
    For Pipe
    Size
    Thread
    Size
    Lg.
    Head
    Wd.
    Head
    Ht.
    Threading
    Thread
    Spacing
    Tensile Strength,
    psi
    Wd.
    Ht.
    Includes
    Each
    Each
    Each
    For Class 125/150 Flanges
    1/2, 3/4
    		1/2"-13
    		2"3/4"11/32"Partially ThreadedCoarse
    		80,0003/4"7/16"4 Hex Head Screws
    4 Hex Nuts    		94368A2230000094368A2250000094368A227000000
    1, 1 1/4
    		1/2"-13
    		2 1/4"3/4"11/32"Partially ThreadedCoarse
    		80,0003/4"7/16"4 Hex Head Screws
    4 Hex Nuts    		94368A111000094368A2260000094368A22800000
    1 1/2
    		1/2"-13
    		2 1/2"3/4"11/32"Partially ThreadedCoarse
    		80,0003/4"7/16"4 Hex Head Screws
    4 Hex Nuts    		94368A224000094368A2110000094368A21200000
    2
    		5/8"-11
    		2 3/4"15/16"27/64"Partially ThreadedCoarse
    		80,00015/16"35/64"4 Hex Head Screws
    4 Hex Nuts    		94368A1120000094368A1250000094368A21300000
    2 1/2, 3
    		5/8"-11
    		3"15/16"27/64"Partially ThreadedCoarse
    		80,00015/16"35/64"4 Hex Head Screws
    4 Hex Nuts    		94368A1130000094368A1260000094368A13800000
    4
    		5/8"-11
    		3"15/16"27/64"Partially ThreadedCoarse
    		80,00015/16"35/64"8 Hex Head Screws
    8 Hex Nuts    		94368A1140000094368A1270000094368A13900000
    6
    		3/4"-10
    		3 1/4"1 1/8"1/2"Partially ThreadedCoarse
    		80,0001 1/8"41/64"8 Hex Head Screws
    8 Hex Nuts    		94368A1150000094368A1280000094368A14100000
    8
    		3/4"-10
    		3 1/2"1 1/8"1/2"Partially ThreadedCoarse
    		80,0001 1/8"41/64"8 Hex Head Screws
    8 Hex Nuts    		94368A1160000094368A1290000094368A14200000
    10, 12
    		7/8"-9
    		4"1 5/16"37/64"Partially ThreadedCoarse
    		80,0001 5/16"3/4"12 Hex Head Screws
    12 Hex Nuts    		94368A11800000094368A13200000094368A144000000
     

    Stainless Steel Heavy Hex Head Screw Kits for Metal Pipe Flanges

    Image of ProductInUse. Shown Installed. Front orientation. Hex Head Screws. Stainless Steel Heavy Hex Head Screw Kits for Metal Pipe Flanges.
    Image of Product. Front orientation. Hex Head Screws. Stainless Steel Heavy Hex Head Screw Kits for Metal Pipe Flanges.

    Shown Installed

    All the hardware you need to join aluminum or stainless steel pipe flanges. These kits come with corrosion-resistant screws and nuts in the right size and number to match your flange's bolt holes. With screw heads and nuts that are about 10% wider than standard, these kits handle heavier loads by distributing them over a larger area. The head also gives you six, flat contact points, so wrenches and sockets won't slip and round off the drive.
    Screw length is measured from under the head. For a tight seal, you’ll also need a gasket between the flanges.
    ASTM Grade B8M—Also known as pressure bolts, these screws meet ASTM standards for use in high-pressure and high-temperature applications. They're also good for cold temperatures.
    316 Stainless Steel—Superior to 18-8 stainless steel screws, these won't degrade when exposed to harsh weather, salt water, and most chemicals.
    Screw
    Nut
    316 Stainless Steel
    Screws and Nuts
    For Pipe
    Size
    Thread
    Size
    Lg.
    Head
    Wd.
    Head
    Ht.
    Threading
    Thread
    Spacing
    Tensile Strength,
    psi
    Wd.
    Ht.
    Includes
    Each
    ASTM Grade B8M for Class 125/150 Flanges
    1/2, 3/4
    		1/2"-13
    		2"7/8"11/32"Partially ThreadedCoarse
    		75,0007/8"31/64"4 Heavy Hex Head Screws
    4 Heavy Hex Nuts    		97755A111000000
    1, 1 1/4
    		1/2"-13
    		2 1/4"7/8"11/32"Partially ThreadedCoarse
    		75,0007/8"31/64"4 Heavy Hex Head Screws
    4 Heavy Hex Nuts    		97755A11400000
    1 1/2
    		1/2"-13
    		2 1/2"7/8"11/32"Partially ThreadedCoarse
    		75,0007/8"31/64"4 Heavy Hex Head Screws
    4 Heavy Hex Nuts    		97755A12100000
    2
    		5/8"-11
    		2 3/4"1 1/16"27/64"Partially ThreadedCoarse
    		75,0001 1/16"39/64"4 Heavy Hex Head Screws
    4 Heavy Hex Nuts    		97755A11500000
    2 1/2, 3
    		5/8"-11
    		3"1 1/16"27/64"Partially ThreadedCoarse
    		75,0001 1/16"39/64"4 Heavy Hex Head Screws
    4 Heavy Hex Nuts    		97755A11200000
    3 1/2, 4
    		5/8"-11
    		3"1 1/16"27/64"Partially ThreadedCoarse
    		75,0001 1/16"39/64"8 Heavy Hex Head Screws
    8 Heavy Hex Nuts    		97755A11600000
    5, 6
    		3/4"-10
    		3 1/4"1 1/4"1/2"Partially ThreadedCoarse
    		75,0001 1/4"47/64"8 Heavy Hex Head Screws
    8 Heavy Hex Nuts    		97755A117000000
    8
    		3/4"-10
    		3 1/2"1 1/4"1/2"Partially ThreadedCoarse
    		75,0001 1/4"47/64"8 Heavy Hex Head Screws
    8 Heavy Hex Nuts    		97755A11800000
     
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