317 Stainless Steel 1.4571 (UNS31700/31703)

 Stainless steel 317

Stainless Steel 317 was designed to be a higher strength alternative to the 316 grades. Composed of larger amounts of chromium, nickel and molybdenum, SS 317 also is more corrosion resistant compared to 316, and tougher than Type 304. This is the due to the high percentage of iron in its composition, which is much higher than many stainless steels. This combination of iron with the chromium-nickel-molybdenum content yields a strong, hardy alloy.

In terms of working capability, all common welding, hot working and cold working practices can be applied. 317 demonstrates good versatility. It will only work harden under cold working, which will also increase its strength. When heat treating this metal, temperatures should not drop below 1700°F as this is the threshold for response.

Stainless steel 317 is commonly found in the textile industry, where its strength and corrosion resistance can be utilized. Other applications include the manufacturing of chemical equipment and the machines used in pulping paper.

Stainless steel 317L

Stainless Steel 317L is the low-carbon derivative of SS 317. The metal maintains its high strength and strong corrosion resistance; however, the carbon content does have several effects. 317L has greater strength under welding; its products are stronger.

Like 317, stainless steel 317L does not respond or harden from heat treatments. When hot working, the metal should be heated ideally within the range of 2100-2300°F. Dropping below 1700°F will cause the metal to be unresponsive. For these reasons, 317L is effective in high temperature areas that experience high rates of chemical corrosion, creep, and stress-to-rupture.

317L is commonly utilized in chemical environments. It has shown itself to be effective in conditions where acids are present, such as acidic chloride. The metal is resistant to corrosion from such substances. As such, it is common to find 317L in equipment used in pulp and paper mills. The acidic environment requires a strength, corrosion resistant metal..

317/317lstainless steel 1.4571 Finished Products Form

• Sheet
• Plate
• Bar
• Pipe & Tube (welded & seamless)
• Fittings
• Elbows, tees, stub-ends, returns, caps, crosses, reducers, pipe nipples, etc.
• Weld Wire (AWS E317L-16, ER317L)

Applications for 317/317l stainless steel

• Oil and Gas industries
• Pharmacy industries
• Textile industries
• Water Piping Systems
• Acid and Chemical industries
• Beverage industries
• Refinery Plants
• Automobile industries
• Cement industries
• Food industries
• Paper and Pulp industries

Equivalents of grade317/317L

ASTM	UNS	EN	DIN	JIS
317	S31700	1.4449	X3CrNiMo18-12-3	SUS317
317L	S31703	1.4438	X2CrNiMo18-15-4	SUS317L

Composition ranges for 317/317L grade of stainless steel

Weight%	C	Mn	Si	Cr	Ni	Mo	P	S	N	Fe
317	0.08 max	2.0 max	0.75 max	18-20	11-15	3-4	0.045	0.030 max	0.10 max	Bal
317L	0.030 max	2.0 max	0.75 max	18-20	11-15	3-4	0.045	0.030 max	0.10 max	Bal

Mechanical Properties

Grade	Tensile Strength ksi (min.)	Yield Strength 0.2% Offset ksi (min.)	Elongation – % in 50 mm (min.)	Hardness (Brinell) MAX	Hardness (Rockwell B) MAX
317	75	30	35	217	95
317L	75	30	40	217	95

Physical Properties

	317	317L	Temperature in °C
Density	7.99 g/cm³	7.99 g/cm³	Room
Specific Heat	0.12 Kcal/kg.C	0.12 Kcal/kg.C	22°
Melting Range	1371 – 1421 °C	1371 – 1421 °C	–
Modulus of Elasticity	193 KN/mm²	193 KN/mm²	20°
Electrical Resistivity	74 µΩ.cm	79 µΩ.cm	Room
Coefficient of Expansion	16.0 µm/m °C	16.0 µm/m °C	20 – 100°
Thermal Conductivity	16.2 W/m -°K	16.2 W/m -°K	20°

Machinability

Grade 317 stainless steel is tougher than 304 stainless steel. It is recommended to use chip breakers. Hardenability of this alloy will be reduced if constant feeds and low speeds are used.

Corrosion Resistance

• Stainless 317/317L has a high tensile and creep strength at elevated temperatures. Due to its excellent corrosion resistance it has been used in handling many of

the chemicals used by the chemical process industries especially in acidic chloride environments such as those encountered in pulp and paper mills. Increased levels

of chromium, nickel and molybdenum compared to 316L stainless steel improve resistance to chloride pitting and general corrosion.

• Good oxidation resistance in continuous service to 925℃ and in intermittent service to 879℃. The corrosion resistance of 317 and 317L should be the same in any

given environment. The one exception is where the alloy will be exposed to temperatures in the chromium carbide precipitation range of 800–1500°F (427–816°C).

Because of its low carbon content, 317L is the preferred material in this service to guard against intergranular corrosion.

• Resistance increases with molybdenum alloy content. 317L is resistant to sulfuric acid concentrations up to 5 percent at temperatures as high as 120°F (49°C). At

temperatures under 100°F (38°C) this alloy has excellent resistance to solutions of higher concentration. However, service tests are recommended to account for

the affects of specific operating conditions that may affect corrosion behavior. In processes where condensation of sulfur-bearing gases occurs, 317L is much more

resistant to attack at the point of condensation than conventional alloy 316. The acid concentration has a marked influence on the rate of attack in such environments

and should be carefully determined by service tests

Heat-treatment Option

1 +A: Annealed (full/soft/spheroidizing)

2 +N: Normalized

3 +NT: Normalized and tempered

4 +QT: Quenched and tempered (water/oil)

5 +AT: Solution annealed

6 +P: Precipitation hardened

Hot working

Grade 317 stainless steel can be hot worked using all common hot working procedures. It is heated at 1149-1260°C (2100-2300°F). It should not be heated below 927°C (1700°F). Post-work annealing can be done to retain the corrosion resistance property.

Cold working

Stamping, shearing, drawing, and heading can be done successfully. Post-work annealing is performed in order to reduce internal stress.

Annealing

1850-2050 F (1010-1121 C) followed by fast cooling.

Hardening

These alloys do not reply to heat treatment. Cold work will cause an increase in both hardness and strength.

Welding

Grade 317L stainless steel can be welded using fusion and resistance methods. Oxyacetylene welding method is not preferred for this alloy. AWS E/ER317 or 317L filler metal can be used to obtain good result.