Standard for U bend Tubes

U弯管管的半成品是换热器管，根据DIN 28180和ASTM A179制造和提供。用于热交换器的管由钢制根据：

• EN 10216-2: P235GH
• DIN 1629：St 37.0
• DIN 17175：ST35.8,15MO3
• A / SA179, steel grades acc to standard
• A / SA 213：T2，T11，T12，T21，T22
• A / SA 556: A2, B2, C2
• 其他类型的钢可以通过协议提供。

你弯曲管s for heat exchangers applied mostly in oil and gas plants, chemical and petrochemical plants, refineries, power plants and renewable energy plants. Low fin tubes can be supplied in the form of U bends.

U-Bend Fabrication Tolerances

U-bend tubes are widely used in heat-exchanger systems. Heat-exchanger equipment on the basis of seamless stainless U-tubes is essential in strategically important and critical fields — nuclear and petrochemical machine building.

物品	Condition (when)	Tolercance
	Nominal bend radius ≤ 2 x nominal OD	less than or equal to 12%
椭圆度	2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD	小于或等于10％
	Nominal bend radius > 4 x nominal OD	小于或等于5％
	Nominal bend radius ≤ 2 x nominal OD	0.75 x nominal wall
Mimimum wall thickness	2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD	0.8 x nominal wall
	Nominal bend radius > 4 x nominal OD	0.9 x名义墙
	标称弯曲半径≤8“（200mm）	+/- 3/64“（1mm）
弯曲半径	8“（200mm）<标称弯曲半径≤16”（400mm）	+/- 1/16“（1mm）
	Nominal bend radius >16" (400mm)	+/-5/64"(1mm)
Disrance between legs		Max 1/16"(1.5mm)
弯曲区域的墙壁变薄		Max 17%
腿部长度之间的差异	腿长≤16'（4.88米）	+1/8“（3mm）
	Leg length > 16' (4.88m)	+3/16"(5mm)
偏离弯曲平面		≤ 3/16"(1.5mm)
Flattening on bend		≤ 10% nominal diameter
直腿长	≤5m	+1/8“（3mm）
	> 5M.	+3/16（5mm）
总管长度包括半径	≤6m	+3/16（5mm）
	> 6M.	+5/16“（8毫米）

U弯管上的尺寸控制

• 椭圆度of straight and bending tube parts
• 稀疏直线和弯曲管零件
• 腿间距长度
• 你弯曲管length (leg + radius + (0,5 x OD))
• 腿长的差异
• 腿的直线度
• 偏离弯曲平面
• Twist of bending portion
• Squareness and cleanliness of tube ends
• 完整的活力ual control

U弯管的热处理

Post bending heat treatment by electrical resistance (Joule effect) is applied. The temperature is monitored and controlled during the process. It is possible to perform the heat treatment in a nitrogen atmosphere.

U弯管可以如下测试

• Hydrostatic Test
• 空气水下测试
• Pulsating Pressure Test
• Dye Penetrant Test
• 磁镜测试

尺寸U弯管的公差是满足以下要求：ASTM A556 / 556M和DIN 28 179

At present Sunny Steel has purchased the equipment for production of the following product range:

可以在协议后生产其他合金和钢等级的管。
Technical requirements

用于弯曲的直管：

• ASTM / ASME SA 179
• SA 213
• ASTM A 789
  
  

U-bend Tubes:

-TEMA RCB 2.31管状交换机制造商协会的标准（第9版）。

-STM A688焊接管焊接管的标准规范，用于饲料水锅炉设计的耐腐蚀钢等级。

- 用于冷凝器和换热器的镍和镍合金管的标准技术要求。

-Customer specifications.