ASTM A688 TP304/316 U Bend Stainless Steel Tube for Heater

• Customization: Available
• Type: Seamless
• Technique: Hot Rolled
• Model NO.: KM-81
• Material: Stainless Steel
• Surface Treatment: Polished
• Usage: Pipeline Transport, Mining, Construction & Decoration, Special Purpose
• Section Shape: Round
• Size: Od 6mm-530mm Wt: 1.00mm-20mm
• Length: 4000-12000mm
• Material Grade: 201/202/304 /304L/316/316L321/310S/409/420/430/440
• Cetificate: ISO
• Package: Standard Export Package
• Payment Term: L/C T/T
• Delivery Time: 15-20 Days Ex.Mill
• Transport Package: in Bundles or Standard Export Seaworthy Packing
• Specification: 1/2′′-42′′
• Trademark: kingmetal
• Origin: China (Mainland)
• Production Capacity: 20000 Ton/Tons / Month

Product Description

ASTM A688 U Bend Stainless Steel Tube Specification

• Heat treatment shall be applied to the U-bend area plus approximately 6 in. [150 mm] of each leg beyond the tangent point of the U-bend after bending, if specified.
• Straight length: max 30000 mm
• Leg length: 12000 mm, points of tangency of the bend to the leg end
• Bending radius: max 1500 mm
• Manufacturing method: cold drawing, cold worked
• Straight length equal to 2 x leg length + 3.1416 x R

Chemical Composition

Elem-Ent	Grade	TP304	TP304L	TP304LN	TP316	TP316L	TP316LN	TP XM-29	TP 304N	TP 316N
%	UNS	S30400	S30403	S30453	S31600	S31603	S31653	S24000	S30451	S31651
C, Max		0.08	0.035	0.035	0.08	0.035	0.035	0.060	0.08	0.08
Mn, Max		2.00	2.00	2.00	2.00	2.00	2.00	11.50-14.50	2.00	2.00
Ph, Max		0.040	0.040	0.040	0.040	0.040	0.040	0.060	0.040	0.040
S, Max		0.030	0.030	0.030	0.030	0.030	0.030	0.030	0.030	0.030
Si,,Max		0.75	0.75	0.75	0.75	0.75	0.75	1.00	0.75	0.75
Ni		8.00-11.00	8.00-13.00	8.00-13.00	10.00-14.00	10.00-15.00	10.00-15.00	2.25-3.75	8.00-1.00	10.00-14.00
Cr		18.00-20.00	18.00-20.00	18.00-20.00	16.00-18.00	16.00-18.00	16.00-18.00	17.00-19.00	18.00-20.00	16.00-18.00
Mo		-	-	-	2.00-3.00	2.00-3.00	2.00-3.00	-	-	2.00-3.00
N		-	-	0.10-0.16	-	-	0.10-0.16	0.20-0.40	0.10-0.16	0.10-0.16

Dimensional Tolerance

ASTM A688 U bend tube tolerance of outside should be accordance with specification A1016/M, bent portion of U tubes for R =2 X D or greater, tolerance shall deviate from the nominal diameter prior to bending by more than 10 %, if less than 2 X D is specified, tolerances could be greater, minimum wall thickness shall not exceed +20 % − 0, average wall thickness are 10 % of the nominal wall thickness, bent area wall tolerance shall not be less than value determined by the equation: 4RT/(4R+D).

Tube Leg Length Tolerance

Leg Length, Ft (M)	Plus Tolerance, In (Mm)
<= 20 (6)	1/8  (3.2)
>20(6), <=30(9)	5/32  (4.0)
>30 (9), <=40 (12.2)	3/16  (4.8)

Squareness Of Ends Tolerance

Tube OD, In, (Mm)	Tolerance, In, (Mm)
<=5.8 (15.9)	0.010 (0.25)
>5.8 (15.9), <=1 (25.4)	0.016 (0.4)

Compared to ASTM A249/A268 specification, ASTM A688 requires more and specific tests to ensure high quality tube, and more tighter tolerances.

Testing & Inspection

• Tensile Strength
• Reverse bending test
• Flattening test
• Flare test
• Flange test
• Dimensional
• Hydrostatic Test
• Pneumatic Test
• Hardness
• Eddy Current test
• Intergranular Corrosion (option)