Alloy 20 Fittings Supplier & Exporter

GENERAL PROPERTIES

Alloy 20 (UNS N08020) is an austenitic, nickel-iron-chromium based super alloy with additions of Copper and Molybdenum which provide resistance to hostile environments, pitting, and crevice corrosion. It is also stabilized with Columbium to minimize carbide precipitation during welding. Alloy 20 appears to fall between both the stainless and nickel categories as it contains characteristics of both. It was designed for maximum resistance to acid attack and demonstrates superior resistance to stress-corrosion cracking in boiling 20% to 40% sulfuric acid, and also has excellent general corrosion resistance to sulfuric acid and to chloride stress corrosion cracking. Alloy 20 has good mechanical properties at both ambient and elevated temperatures, up to approximately 930°F (500°C) and is readily fabricated by usual industrial processes.

APPLICATIONS

Alloy 20 was originally designed for use in sulfuric acid related applications; however, it is now frequently used in a wide variety of industries. Applications that commonly use Alloy 20 include:

• Chemical and allied industries
• Food and dye production
• Heat exchangers
• Explosives
• Tanks
• Valves
• Pickling racks
• Manufacture of synthetic rubber and plastics
• Pharmaceuticals
• SO2 scrubbers and other severe environments

CORROSION RESISTANCE

• Excellent resistance to general corrosion, pitting, and crevice corrosion in chemicals containing chlorides and sulfuric, phosphoric, and nitric acids.
• Nickel content aids in chloride ion stress and corrosion resistance.
• Additions of Copper and Molybdenum provide resistance to hostile environments, pitting, and crevice corrosion.
• Chromium adds to its resistance of oxidizing environments such as nitric acids.
• Columbium reduces the effects of carbide precipitation.

WELDABILITY

• All commonly used welding methods, with the exception of oxyacetylene, can be successfully used.
• The presence of Columbium tends to minimize the precipitation of carbides in the heat-affected zone, so the material may be used in the as-welded condition in most cases.
• Pre-heating is not required.

HEAT TREAMENT

• Cannot be hardened by heat treatment.
• Stabilized-annealing is done at 1750-1850°F, followed by water quenching.
• Stress relieving can be performed on annealed material up to 950°F.

PROCESSING - HOT FORMING

• Heat uniformly to a starting temperature of 2100-2225°F. Finish forging before the stock drops below 1800°F.
• In order to stabilize the material after hot working operations, reheat at 1750-1850°F for a minimum of 1/2-hour per one inch of thickness and water quench.

PROCESSING - COLD FORMING

• Alloy 20 has good cold formability. Bending, drawing and pressing, and other forming operations that occur in the production of fabricated items are readily performed.
• Alloy 20 can normally be press brake bent over a radius twice the materials thickness.
• After cold reductions of more than 15%, a final stabilizing annealing is often required.

MACHINABILITY

Because of Alloy 20′s high work-hardening rate the following are required:

• Only low surface-cutting speeds are possible compared with low-alloy standard austenitic stainless steel.
• Tools should be engaged at all times.
• Heavy feeds are important in getting below the work-hardened 'skin'.

CHEMICAL PROPERTIES:

MECHANICAL PROPERTIES:

PHYSICAL PROPERTIES:

Fittings and Flanges for Stainless Steel Pipe
Stainless steel piping systems can be joined by butt welding and, in the heavier 40S and 80S schedules, with threaded connections.

BUTT WELDING STAINLESS STEEL PIPE FITTINGS

Harsh steel stocks butt welding fittings in the following configuration.

• Elbows 45 degree and 90 degree - long radius and short radius.
• Return bends 180 - long radius and short radius.
• educers - concentric and eccentric.
• Tees - equal and reducing.
• Caps.
• Stub ends - Type B.

Advantages of stainless steel butt Weld fitting to the pipe are to keep pipes permanently leak proof. The continuous structure helps strength between pipes and fittings. It reduces pressure and also minimises the action of corrosion and erosion. Butt welding fittings can be supplied in either seamless or welded construction and are covered by specifications ASTM A403M and ASTM A815M for Duplex grades.

STAINLESS STEEL SCREWED AND SOCKET WELD FITTINGs

Stainless steel piping systems can be connected using stainless steel screwed fittings - BSP threaded ("150lb") low pressure stainless steel fittings and NPT class 3000 high pressure stainless fittings in Grade 316. Socket weld fittings are used in high pressure piping systems and available in grade 316L to suit schedule 80S wall thickness piping.

MANUFACTURING SPECIFICATIONS:

• ASTM A182M (3000lb NPT and socket weld).
• ANSI B16.3 (BSP dimensions)
• ISO 4144 (BSP dimensions)

STAINLESS STEELS FITTINGS AND FLANGES:

A flange is a ring of steel (forged, cut from plate, or rolled) designed to connect sections of pipe, or to join pipe to a pressure vessel, valve, pump or other integral flanged assembly. Flanges are joined to each other by bolts, and to the piping system by welding or threading (or loose when stub ends are used). Forged stainless steel flanges are designed to the following common pressure ratings, stainless steel flanges are exported by Harsh Steel in Classes 150, 300, 600, 900, 1500 and 2500. Standard sealing face is Raised Face (RF).
The basic types of flanges are:

• Stainless steel slip-on flange
• Stainless steel socket weld flange
• Stainless steel blind flange
• Stainless steel lap joint flange
• Stainless steel weld neck flange
• Stainless steel threaded flange
• Stainless steel orifice Flange

Manufacturing specification: ASTM A182M
Plate stainless steel flanges are cut and machined from plate - Table 'D', Table 'E', etc.
Manufacturing specification: AS2129.
Types and applications of Stainless steel and Nickel alloy flanges

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