Slip-On Flange Manufacturer
A slip-on flange is one of the simplest parts on a piping drawing, which is exactly why sourcing problems with it are so frustrating. A grade that cannot be traced back to its heat, a bore that is out of tolerance so the pipe will not seat, a mill test report that does not match the part: any one of those holds up fit-up and pushes a shutdown or construction schedule.
MFC Flange is a slip-on flange manufacturer that forges, machines, heat treats, and tests every flange in one ISO 9001:2015-certified facility in Sealy, Texas, so the part that arrives on site matches the spec it was ordered to.
Why Engineers Specify Slip-On Flanges
A slip-on flange slides over the outside of the pipe and is attached with two fillet welds, one at the hub on the outside diameter and one at the bore face on the inside. Because the pipe sits inside the flange instead of butting against it, the joint needs less precision in pipe cut length, and alignment is easier to adjust during fit-up than with a butt-welded connection.
That design makes slip-on flanges a common choice for:
- Lower-pressure process, utility, and cooling water lines
- Systems where installation speed and field adjustment matter
- Projects where the lower forging weight helps control material cost
For high-pressure, high-temperature, or cyclic-loading service, most piping codes and engineers move to a butt-welded connection. In those cases, MFC Flange’s weld neck flanges provide the tapered hub and full-penetration weld that the application calls for. Having both styles from the same slip-on flange manufacturer keeps a mixed bill of materials on one purchase order and one material record.
Request A Quote
Send your material grade, size, pressure class, and quantity through the quote request form and the MFC Flange team will respond with pricing and lead time. Expedited turnaround is available as fast as 24 hours on stock material grades. For questions on a drawing, a spec, or a material substitution before you submit, contact the MFC Flange team directly.
Forged, Machined, and Tested Under One Roof
Most slip-on flange buyers deal with a chain of vendors: one shop forges, another machines, a third tests. Each handoff adds lead time and another set of paperwork to reconcile. MFC Flange handles every stage in-house through its forging, machining, heat treating, and testing capabilities:
- Forging: Open-die and closed-die forging on 300 to 1,000 ton mechanical, hydraulic, and hammer presses
- Machining: In-house turning, milling, and drilling of the bore, face, and bolt holes
- Heat treating: Annealing, solution heat treatment, normalizing, stress relief, and water quenching
- Testing: Factory acceptance testing, positive material identification (PMI), chemical analysis, tensile, hardness, Charpy impact, and non-destructive evaluation (UT and LP)
Keeping production in one building means the forging, the heat treat record, and the test results for a slip-on flange all tie back to the same part number.
Stainless Steel Slip-On Flanges and Alloy Grades
As a stainless steel slip-on flange manufacturer, MFC Flange works primarily in 300 Series grades for corrosive and sanitary service. Beyond stainless, slip-on flanges are available in duplex, nickel alloy, and chrome-moly grades for applications where corrosion, temperature, or chloride exposure rule out standard materials.
Material Family Grades
- 300 Series Stainless Steel: 304/H, 304/L, 310/H, 316/H, 316/L, 317/L, 321/H, 347/H
- Duplex and Duplex Stainless Steel: F44, Duplex F51/60 & Super Duplex F53, F55
- Nickel Alloys Hastelloy: C276, C22, Inconel A625, Monel A400, Nickel 200, Alloy 600, Alloy 20, Alloy 825, Alloy 800/H/HT
- Chrome-Moly Alloys: A182 F5, F9, F11, F22, F91
Full grade details and application notes are on the materials page. For grade-by-grade guidance on 300 Series options, see stainless steel flanges.
Pressure Classes, Standards, and Face Types
MFC Flange manufactures slip-on flanges to the dimensional standards procurement teams already specify:
- ASME B16.5 for standard pipe flange sizes
- DIN EN 1092 for international projects
- Pressure classes: Class 150 through Class 2500
- Face types: raised face (RF) and flat face (FF)
Slip-on flanges are part of the full commodity flanges product line, which also covers blind, socket weld, threaded, lap joint, and orifice flanges.
Industries That Use MFC Flange Slip-On Flanges
Slip-on flanges from MFC Flange go into piping systems for oil and gas, chemical processing, petrochemical, power generation, marine and shipbuilding, and defense projects. See how MFC Flange supports each sector on the industries page.
Certifications That Support Compliant Procurement
Choosing an ISO-certified slip-on flange manufacturer gives QA and procurement teams a documented quality system for every part, not just a certificate in a sales packet. MFC Flange’s certifications and compliance include:
- ISO 9001:2015 certification through ANAB
- Manufacturing to ANSI, ASME, ASTM, DIN EN, and PED standards
- 100% DFARS compliant materials inventory
- AIS and BABA compliance for federally funded infrastructure projects
- Canadian Registration Numbers across Alberta, Quebec, Ontario, Manitoba, Newfoundland, Nunavut, Nova Scotia, PEI, NWT, New Brunswick, and Yukon
Frequently Asked Questions
What is a slip-on flange used for?
A slip-on flange connects pipe to valves, equipment, or other pipe in lower-pressure systems where easy alignment and faster installation are priorities. The pipe slides into the flange bore and is fillet welded on the inside and outside.
What is the difference between a slip-on flange and a weld neck flange?
A slip-on flange fits over the pipe and is attached with two fillet welds, while a weld neck flange is butt welded to the pipe through a tapered hub. Weld neck flanges handle higher pressure, temperature, and cyclic loading, and slip-on flanges cost less and are easier to align during installation.
What materials does MFC Flange use for slip-on flanges?
MFC Flange manufactures slip-on flanges in 300 Series stainless steel, duplex and super duplex stainless, nickel alloys such as Hastelloy, Inconel, and Monel, and chrome-moly grades including A182 F5, F9, F11, F22, and F91.
Is MFC Flange an ISO certified slip-on flange manufacturer?
Yes. MFC Flange holds ISO 9001:2015 certification through ANAB, and every slip-on flange is forged, machined, heat treated, and tested in its Sealy, Texas facility.