GB/T18984 Low-temperature heat exchanger tubes

GB/T18984-2003 standard suitable for -49 to -148 degrees F cryogenic pressure vessel piping, and low-temperature heat exchanger tubes seamless steel pipe.

GB/T18984 Low-temperature heat exchanger tubes seamless steel pipe
Out diameter and Wall thickness

The pipe diameter (D) and wall thickness (S) tolerances shall comply with the requirements in Table 1.

Process Size(mm) Tolerance
Hot-rolled O.D. <351  +/-1.0% D(+/-0.50min)
>=351  +/-1.25% D
W.T. <=25  +/-12.5% S(+/-0.40 min)
Cold drawn O.D. <=30  +/-0.20
30-50  +/-0.30
>50  +/-0.75% D
W.T. <=3  +12.5% S, -10% S
>3  +/-10% S

Note: 
Outside diameter greater than or equal to 351 thermal Flaring wall thickness allowable deviation: Guests 15 write S

Chemical Compositions(%)
Grade C Si Mn P(max) S Ni Mo V
16MnDG 0.12-0.20 0.20-0.55 1.20-1.60 0.025 0.025  -  -  -
10MnDG <=0.13 0.17-0.37 <=1.35 0.025 0.025  -  - <=0.07
09DG <=0.12 0.17-0.37 <=0.95 0.025 0.025  -  - <=0.07
09Mn2VDG <=0.12 0.17-0.37 <=1.85 0.025 0.025  -  - <=0.12
06Ni3MoDG <=0.08 0.17-0.37 <=0.85 0.025 0.025 2.5-3.7 0.15-0.30 <=0.05
Longitudinal mechanical properties of the steel pipes
Grade Tensile strength Lower yield strength(Rcl/Mpa) Elongation
Rm/Mpa W.T.<=16mm W.T.>16mm A/%
16MnDG 490-665 >=325 >=315 >=30
10MnDG >=400 >=240 >=35
09DG >=385 >=210 >=35
09Mn2VDG >=450 >=300 >=30
06Ni3MoDG >=455 >=250 >=30

(Not more than 25 mm) outside diameter and wall thickness of the steel pipe shall conform to GB/T 17395-1998 Table 1 provisions. According to the requirements of the demand side, the supply and demand sides consultation, produce the provisions specifications steel pipe.

Tubing shall be made seamless, plain or upset and coupling with high-seal connections. Coupling-free connections are possible.



Tech & Service of Seamless pipe

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.

How to make seamless pipe(seamless pipe process)?
Hot Piercing Workshop
Piercing process
The cross roll piercing and pilger rolling process in the size range from approx. 250 to 660 mm outside diameter.
Precision cold drawn steel tube production process
Pipe weld cracks
often follow different mechanisms can be divided into two types of thermal cracking and cold cracking.
How to calculate a steel pipe and tube theoretic weight
Calculate a steel pipe?
Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe.
Pipe beveling
Pipe beveling is the process where an angle is formed between the edge of the end of a pipe or tube and a plane perpendicular to the surface.
Steel pipe cutting machine
Pipe cutting
Cutting tools have a grinding wheel piece cutting machine (also known as toothless saw), hand saw, cutter and other hand tools.
Packing the steel pipes
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method.


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