St37.4 Cold Drawn BA Seamless Steel Tube for Hydraulic System
1. Descripition of St37.4 Cold Drawn BA Seamless Steel Tube for Hydraulic System
the steel billets is from Baosteel, Xingcheng Special Steel or Huaisteel, we do 100% visual inspection and chemical inspection randomly, then bars were cut into short pcs as per requirement of final tube length requirement to do hot piercing
2. Specification ofSt37.4 Cold Drawn BA Seamless Steel Tube for Hydraulic System
2.1 Dimensions
Tubes shall be ordered:
2.1.1. by outside diameter and inside diameter
2.1.2. by outside diameter and wall thickness
Delivery conditions and heat treatment
BK (+C) Cold finished/hard (cold finished as drawn). No heat treatment after the last cold forming process
BKW (+LC) Cold finished/soft (lightly cold worked). After the last heat treatment there is a light finishing pass (cold drawing).
BKS (+SR) Cold finished/stress relieve annealed. After the final cold forming process the tubes are stress relieve annealed.
GBK (+A) Annealed. After the final cold forming process the tubes are annealed in a controlled atmosphere.
NBK (+N) Normalized. After the final cold forming process the tubes are annealed above the upper transformation point in
Surface condition
Tube surface corresponds to the standards and depends on the method of tube manufacturing and method of heat treatment. Value of roughness Ra <0.8 µm.
Tube ends
The tubes are delivered with plain ends without burrs at the ends of the tube.
Upon request ends could be plugged with plastic caps
3.Testing ofDIN Cold Drawn High Precision Carbon Steel Tube
Testing is performed in accordance with corresponding standards or by agreement
• flattening test , drift expanding test, flaring test, bending test
• mechanical properties test
• NDT for detection of transverse imperfections and wall imperfections
Packing and Protective coating
4.1 Tubes are supplied either uncoated or with the manufacturers standard mill coating at the option of the customer (subject of agreement between customer and manufacturer).
