Cast Iron Flange

QS Flange: Cast Iron Flange Chinese Factory

Ductile iron cast flange to ASME B16.42 in Class 150 and 300, 1/2 to 24 inch, flat face and black anti-rust coating for water treatment, HVAC and process piping.

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One-Minute Overview

Cast ductile iron flange to ASME B16.42 in Class 150 and Class 300.
Sizes 1/2 to 24 inch, flat face throughout, black anti-rust coating.
Outside diameter runs from 89 mm at 1/2 inch to 819 mm at 24 inch Class 300.
Built for water treatment, HVAC, petrochemical and construction piping.

A cast iron flange is the cost-effective answer for lower pressure water and utility piping, and this one is cast in ductile iron rather than grey iron. Ductile iron carries noticeably better tensile strength and impact toughness than grey iron, which matters on buried mains, in pump rooms and in plant rooms where a flange takes bending from pipe that is never perfectly aligned. The series follows ASME B16.42 in Class 150 and Class 300, from 1/2 to 24 inch, with a flat face throughout and a black anti-rust coating.

Name: Cast Iron Flange
Size: 1/2"-24"
Pressure: 150LB/300LB
Flange Face: FF
Surface: Black
Material: Ductile Iron
Process Method: Casting
Standard: ASME B16.42

Dimensions scale predictably with size and class. Outside diameter starts at 89 mm for a 1/2 inch Class 150 and reaches 819 mm at 24 inch Class 300, with the Class 300 pattern always the larger of the two. Bolt circle diameter runs from 60.3 mm to 577.8 mm, and the drilling follows: four 15.9 mm holes on the 1/2 inch pattern, twenty four 38.1 mm holes on 24 inch Class 300. Flange thickness climbs from 11.1 mm to 41.3 mm over the same span. Those figures let a fitter check a delivered flange against the mating valve or pump with a tape and a bolt gauge before it goes anywhere near the line.

The flat face is deliberate. FF flanges pair with full face gaskets and spread bolt load across the whole flange, which suits cast bodies and the softer seating of iron valves and pumps; a raised face would add bending the casting does not need. Specify size, class and drilling when you order, and note that the casting can be supplied in other coatings or machined to a modified drilling where a project asks for it.

FAQ

Q1. What is ASME B16.42 and does it cover Class 300?

ASME B16.42 is the dimensional and pressure-temperature standard for ductile iron flanges in Class 150 and Class 300. It fixes outside diameter, bolt circle, hole count and thickness for each size, so a 6 inch Class 150 flange from this series matches any other B16.42 flange in that size and class, whatever the foundry.

Q2. Why ductile iron and not ordinary cast iron?

Because ductile iron bends before it breaks. Its graphite sits as nodules instead of flakes, which lifts tensile strength and impact toughness, and that is what you want on a buried main or a pump connection where the pipe is never perfectly aligned. Grey iron is cheaper and fine for light duty; ductile is the safer casting for real plant conditions.

Q3. Can I bolt a flat face cast flange to a raised face steel one?

You can, and people do, but it is a compromise. Flat face against raised face leaves the gasket sitting on a step, so the load is uneven and the joint is easier to over-stress. The clean answer is a full face gasket sized for the flat side, or a flat faced mating flange. If you are stuck with the mix, say so and we will talk gaskets.

Q4. How long will production take?

Standard sizes are typically ready within 30 days, and in-stock items ship immediately. Larger or custom orders get a confirmed date per order, because the schedule depends on quantity, material, the bolt pattern you specify, and how busy production is at the moment you order.

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