Stainless Steel 316L Fittings, UNS S31603 Fittings Supplier & Exporter

GENERAL PROPERTIES

Alloy 316/316L is molybdenum-bearing austenitic stainless steel. The higher nickel and molybdenum content in this grade allows it to demonstrate better overall corrosion resistant properties than 304, especially with regard to pitting and crevice corrosion in chloride environments. In addition, Alloy 316/ 316L provides excellent elevated temperature tensile, creep and stress-rupture strengths, as well as outstanding formability and weldability. 316L is the lower carbon version of 316 and is immune from sensitization; therefore, it is very frequently used in heavy gauge welded components.

APPLICATIONS

• Food preparation equipment, especially in chloride environments
• Chemical processing, equipment
• Laboratory benches and equipment
• Rubber, plastics, pulp & paper machinery
• Pollution control equipment
• Boat fittings, value and pump trim
• Heat exchangers
• Pharmaceutical and textile industries
• Condensers, evaporators and tanks

CORROSION RESISTANCE

• Generally more resistant than 304 in range of atmospheric environments and many corrosive media due to the increased chromium
  and molybdenum content.
• Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 122°F (50°C).
• Considered resistant to potable water with up to about 1000mg/L chlorides at ambient temperatures, reducing to about 500mg/L at
  140°F (60°C).
• Usually regarded as the "marine grade stainless steel" – but is not resistant to warm sea water.

HEAT RESISTANCE

• Good oxidation resistance in intermittent service to 1600°F (870°C) and in continuous service to 1700°F (925°C)
• Grade 316L is more resistant to carbide precipitation.

WELDING CHARACTERISTICS

• Excellent weldability by all standard fusion methods, both with and without filler metals.
• Heavy welded sections in Grade 316 require post-weld annealing for maximum corrosion resistance, this is not required for grade 316L.

HEAT TREATMENT

• Annealing temperature range is 1900 to 2100°F (1038 to 1149°C).
• Cannot be hardened by heat treatment.
• Special consideration is needed to compensate for a higher coefficient of thermal expansion to avoid warping and distortion.

PROCESSING - HOT FORMING

• Most producers recommend a maximum forging temperature between 2100°F and 2300°F
• Do not forge below 1700°F (927°C) Best
• Corrosion resistance is obtained if the forgings are given a final anneal.

PROCESSING - COLD FORMING

• 316/316L types being extremely tough and ductile, can be readily cold worked such as roll form, swaging, cold heading, deep drawing,
  bent, etc., without difficulty
• Severely cold formed parts should be annealed to remove stresses.

MACHINEABILITY

• Type 316/316L is somewhat more difficult to machine than Type 304 because of its toughness.
• 316/316L machines with chip characteristics that are tough and strong.
• Chip breakers and curlers are advised.
• As large a tool as possible and great amounts of cutting fluid should be used.
• Heavy positive feeds at low speeds should be considered since 316/316L work hardens rapidly.

CHEMICAL PROPERTIES:

	C	Mn	Si	P	S	Cr	Mo	Ni	N
316 (S31600)	0.08 max	2.0 max	0.75 max	0.045 max	0.03 max	min: 16.0 max: 18.0	min: 2.0 max: 3.0	min: 10.0 max: 14.0	0.10 max
316L (S31603)	0.03 max	2.0 max	0.75 max	0.045 max	0.03 max	min: 16.0 max: 18.0	min: 2.0 max: 3.0	min: 10.0 max: 14.0	0.10 max

MECHANICAL PROPERTIES:

Grade	Tensile Strength ksi (min)	Yield Strength 0.2% ksi (min)	Elongation %	Hardness (Brinell) MAX	Hardness (Rockwell B) MAX
316 (S31600)	75	30	40	217	95
316L (S31603)	70	25	40	217	95

PHYSICAL PROPERTIES:

Density lbm/in3	Thermal Conductivity (BTU/h ft. °F)	Electrical Resistivity (in x 10-6)	Modulus of Elasticity (psi x 106	Coefficient of Thermal Expansion (in/in)/°F x 10-6	Specific Heat (BTU/lb/°F)	Melting Range (°F)
0.29 at 68°F	100.8 at 68 212°F	29.1 at 68°F	29	8.9 at 32 – 212°F	0.108 at 68°F	2500 to 2550
				9.7 at 32 – 1000°F	0.116 at 200°F
				11.1 at 32 – 1500°F

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

Slip-on flanges	The flange is slipped over the pipe and then welded both inside and outside to provide sufficient strength and prevent leakage. Slip-on flanges are also used as loose back-up flanges when stub ends are used.
Blind flanges	This is a flange without a centre bore, used to shut off a piping system or vessel opening
Weld neck flanges	This is a flange without a centre bore, used to shut off a piping system or vessel opening
Lap joint flanges	This is again similar to a slip-on flange, but has a radius at the intersection of the centre bore and the flange face to accommodate a lap stub end.

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