AISI 316L Round Bars

AISI 316L hot rolled round bar is the low carbon, molybdenum bearing austenitic bar specified for welded chloride service.

16 to 125 mm Austenitic stainless steel Made to order

HOT ROLLED ROUND BARS

AISI 316L hot rolled round bar

AISI 316L hot rolled round bar is a molybdenum bearing austenitic stainless bar, rolled from 16 to 125 mm diameter and supplied solution annealed. It is the low carbon version of AISI 316. Carbon is held to 0.03 percent, which limits sensitisation, the forming of chromium carbides at the grain boundaries during welding that leaves the metal beside them short of chromium and open to attack. Bar that will be welded, and that cannot be annealed again afterwards, is therefore ordered as 316L rather than 316. Against 304L the difference is the 2 to 3 percent molybdenum, which raises resistance to pitting and crevice attack in chloride bearing water, brine and several process acids. Both grades carry the same annealed strength minima, so the choice rests on the service rather than on load.

The bar leaves the mill solution annealed, the condition that holds the carbides in solution and leaves the steel softest and most corrosion resistant; ASTM A276 sets 485 MPa tensile and 170 MPa yield as the annealed minima. The grade does not harden by heat treatment and is non-magnetic when annealed, so strength above those minima comes only from cold work. It work hardens under a blunt edge, and machining calls for sharp tools, positive rake, a steady feed and plenty of coolant. Welding needs no preheat and, at this carbon level, no anneal afterwards. Laxcon Steels rolls the bar to order for pump and valve shafts, seawater and brine pipework fittings, marine fasteners and pins, and shafts for food, dairy and pharmaceutical plant.

Composition limits in weight percent are carbon 0.03 maximum, manganese 2.0 maximum, sulphur 0.03 maximum, phosphorus 0.045 maximum, silicon 0.75 maximum, chromium 16.0 to 18.0, nickel 10.0 to 14.0, molybdenum 2.0 to 3.0 and nitrogen 0.1 maximum.

SPECIFICATION

AISI 316L hot rolled round bar supply conditions

Size range: 16 mm - 125 mm (5/8" - 5")
Length: Up to 8 metres
Tolerances: ASTM A484, EN10060
Heat treatment: Solution annealing
Grade: AISI 316 L (316L, SS 316L, SUS 316L, 1.4404)
Family: Austenitic stainless steel
Supply: Made to order in this grade; every published size of the form

Composition of AISI 316L

Element	Symbol	Minimum %	Maximum %
Carbon	C		0.03
Manganese	Mn		2.0
Sulphur	S		0.03
Phosphorus	P		0.045
Silicon	Si		0.75
Chromium	Cr	16.0	18.0
Nickel	Ni	10.0	14.0
Molybdenum	Mo	2.0	3.0
Nitrogen	N		0.1

Composition, weight percent, balance iron. From the Laxcon Steels grade reference.

Equivalents of AISI 316L

Standard	Designation
UNS	S31603
EN number	1.4404 (X2CrNiMo17-12-2)
JIS	SUS 316L

Equivalence means nearest counterpart, not identity: each standards body sets its own composition window, so the limits of the standard named on the order govern.

Pitting resistance

The pitting resistance equivalent number of AISI 316L runs from 22.6 at the specified minimum chromium, molybdenum and nitrogen to 29.5 at the maxima, computed as PREN = Cr + 3.3Mo + 16N (International Molybdenum Association). It ranks resistance to chloride pitting against other austenitic and duplex grades and nothing else: it does not predict crevice corrosion, stress corrosion cracking or service life. The pitting resistance reference carries the full table.

Governing standards

EN 10088-3: Stainless steels: technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products for general purposes. Composition, heat treatment condition and mechanical properties per grade.
EN 10060: Hot rolled round steel bars for general purposes: dimensions and tolerances on shape and dimensions.
ASTM A276/A276M: Stainless steel bars and shapes: composition, condition, mechanical properties and finish designations for hot-finished and cold-finished bar.
ASTM A484/A484M: General requirements for stainless steel bars, billets and forgings: permissible variations in dimensions, straightness, weight and length, and the test and marking requirements every bar order inherits.
ASTM A479/A479M: Stainless steel bars and shapes for use in boilers and other pressure vessels: the bar specification a pressure-part drawing calls for.
ASTM A314: Stainless steel billets and bars for forging.
NACE MR0175 / ISO 15156: Materials for use in H2S-containing environments in oil and gas production: the sour-service limits on hardness and condition.
EN 10204: Metallic products, types of inspection documents: the 2.2 test report and the 3.1 and 3.2 inspection certificates a purchase order can call for.

Weight per metre

Diameter (mm)	kg per metre	Metres per tonne
16	1.59	629.5
17	1.79	557.6
18	2.01	497.4
19	2.24	446.4
20	2.48	402.9
21	2.74	365.4
22	3.00	333.0
23.2	3.34	299.4
24	3.57	279.8
25	3.88	257.9
26	4.19	238.4
27	4.52	221.1
28	4.86	205.6
30	5.58	179.1
32	6.35	157.4
34	7.17	139.4
36	8.04	124.4
37	8.49	117.7
38	8.96	111.6
40	9.93	100.7
42	10.95	91.4
45	12.57	79.6
47	13.71	73.0
48	14.30	69.9
50	15.51	64.5
53	17.43	57.4
56	19.46	51.4
57.5	20.52	48.7
60	22.34	44.8
63	24.63	40.6
66	27.03	37.0
67.5	28.27	35.4
70	30.40	32.9
73.5	33.52	29.8
75	34.90	28.7
77.5	37.27	26.8
80	39.71	25.2
83	42.75	23.4
85	44.83	22.3
88	48.05	20.8
90	50.26	19.9
93	53.67	18.6
95	56.00	17.9
98	59.59	16.8
100	62.05	16.1
105	68.41	14.6
106	69.72	14.3
110	75.08	13.3
115	82.06	12.2
120	89.35	11.2
125	96.95	10.3

Density 7.90 g/cm³, diameter squared x 0.006205. Sizes are the published range at the nominal diameters shown.

Ordering AISI 316L hot rolled round bar

An enquiry for this grade in this form states the grade and its governing standard (EN 10088-3, or ASTM A276 and ASTM A479, with NACE MR0175 / ISO 15156 where the service is sour), the solution annealed condition, the diameter with its tolerance to ASTM A484 or EN 10060, the finish as black, spot ground or fully ground, the length, the quantity, the EN 10204 certificate type, and any ultrasonic test or PMI check required.