ASTM A350 LF2 Weld Neck Flange Order

On February 3, 2025, a regular customer from Russia sent us an inquiry about ASTM A350 LF2 weld neck flange.This material grade and product type are common for us, so we quickly completed the quotation and the customer placed the order a week later.

ZIZI is a professional manufacturer specializing in the production and processing of flanges. Our products are mainly used in the chemical, oil, gas, water conservancy, power generation and marine engineering industries. Our products cover a wide range of flanges in various materials and sizes. We offer a wide range of materials including carbon steel, stainless steel, alloy steel, cryogenic steel, duplex steel and super alloys.

ASTM A350 LF2 Weld Neck Flange Inspection：

Appearance Inspection

✅Surface defects: no cracks, pores, slag.

✅Processing quality: sealing surface finish, scratches and so on.

✅Clear marking: material labeling, pressure level (e.g. Class300), size (e.g. DN150), etc.

Size inspection

✅Key dimensions: measure the outer diameter (OD), inner diameter (ID), bolt hole center circle diameter (PCD), number of holes / hole diameter, flange thickness (T), neck height / angle (RTJ surface need to check the sealing groove).

✅Standard compliance: Check ASME B16.5 standard.

✅Matching compatibility: Ensure matching dimensions with valves/pipes (e.g. convex RF/concave FF).

WN Flange Specifications:

Shape Type	Regular and Long Neck
Sealing Face	RF, FF, FTJ
Size Range	1/2″ – 48″/ DN15 – DN1200
Pressure Rating	Class 150, 300, 600, 900, 1500, 2500lb
Standard	ASME B16.5, ASME B16.47 Series A/B

ASTM A350 LF2 WN Flange Material Analysis：

Chemical Composition：

CHEMICAL	LIMITS	C	Mn	P	S	Si	Cu	Ni	Cr	Mo	V	Nb
ASTM A350 LF2	MIN		0.60			0.15
	MAX	0.30	1.35	0.035	0.040	0.35	0.40	0.40	0.30	0.12	0.08	0.02

Mechanical Properties：

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %	HARDNESS
ASTM A350 LF2	485-655	250 min	22 min	30 min	197 max

Weld Neck Flange Dimension:

Weld Neck flange sizes range from 1/2“ to 24” and pressure ratings include 150#, 300#, 400#, 600#, 900#, 1500# and 2500#. Sealing surfaces include raised face (RF), flat face (FF), ring joint (RTJ), tongue and groove (TG), and dimple face (MFM).

Weld neck Flange Dimensions Class 300 (ASME B16.5 ) in Millimeters：

Nominal Pipe Size		A	B	C	D	E	F	G	H	I	J	Weight
inch	mm	mm	mm	mm	mm	mm	mm	mm	Holes	mm	mm	kg / piece
1/2	21.30	95.20	15.70	14.20	52.30	21.30	38.10	35.00	4	15.70	66.55	0.75
3/4	26.70	117.3	20.80	15.70	57.15	26.70	47.70	42.90	4	19.00	82.50	1.26
1	33.40	123.9	26.70	17.50	62.00	33.50	53.80	50.80	4	19.00	88.90	1.52
1 1/4	42.20	133.3	35.10	19.00	65.00	42.20	63.50	63.50	4	19.00	98.50	2.03
1 1/2	48.30	155.4	40.90	20.60	68.30	48.30	69.85	73. 15	4	22.30	114.3	2.89
2	60.30	165. 1	52.60	22.30	69.85	60.45	84.00	91.90	8	19.00	127.0	3.4
2 1/2	73.00	190.5	62.70	25.40	76.20	73.15	100.0	104.6	8	22.30	149.3	5.17
3	88.90	209.5	78.00	28.40	79.25	88.90	117.3	127.0	8	22.30	168.1	6.93
3 1/2	101.6	228.6	90.20	30.20	81.00	101.6	133.3	139.7	8	22.30	184.1	8.67
4	114.3	254.0	102.4	31.70	85.80	114.3	146.0	157.2	8	22.30	200.1	11.2
5	141.3	279.4	128.3	35.00	98.50	141.2	177.8	185.7	8	22.30	234.9	15.1
6	168.3	317.5	154.2	36.50	98.50	168.4	206.2	215.9	12	22.30	269.7	19.1
8	219.1	381.0	202.7	41.10	111.2	219.2	260.3	269.7	12	25.40	330.2	29.9
10	273.0	444.5	254.5	47.70	117.3	273.0	320.5	323.8	16	28.40	387.3	42.7
12	323.8	520.7	304.8	50.80	130.0	323.8	374.6	381.0	16	31.70	450.8	61.8
14	355.6	584.2	To be specified by the Purchaser	53.80	142.7	355.6	425.4	412.7	20	31.70	514.3	85.8
16	406.4	647.7		57.15	146.0	406.4	482.6	469.9	20	35.00	571.5	106
18	457.2	711.2		60.45	158.7	457.2	533.4	533.4	24	35.00	628.6	131
20	508.0	774.7		63.50	162.0	508.0	587.2	584.2	24	35.00	685.8	158
24	609.6	914.4		69.85	168.1	609.6	701.5	692.1	24	41.10	812.8	230

Advantages of Low Temp Carbon Steel WN Flange：

•Low Temperature Toughness: High impact resistance is maintained below -50℃.

•Anti-brittle fracture: Special alloy composition (Ni/Cr) prevents brittle fracture at low temperature.

•Reliable sealing: finely machined sealing surfaces to avoid cold shrinkage leakage.

•Standards compatibility: Comply with ASME B16.5 and other low temperature flange specifications.

•Long life: excellent fatigue and corrosion resistance in low temperature environment.

Areas of Application:

Oil & Gas Industry

Chemical & Petrochemical Industry

Power Industry

Ship & Marine Engineering

Food & Pharmaceutical Industry

Other Industries