GB/T 20409 Multi - Rifled Seamless Steel Tubes For High Pressure Boiler

GB/T 20409 Multi-rifled Seamless Steel Tubes for High-pressure Boiler

Application:High-quality carbon structural steel, alloy structural steel cold-drawing or cold-rolled internal thread tube for boilers suitable for producing high pressure and above pressure

Size:Length--8-12m
OD--28.6-66.7mm
WT--6.38-18.33mm
Curvature--≤1.0mm/m

Surface Quality:
1.The internal and external surfaces of female threaded tubes are not allowed to have cracks, folds, knots, folds, and delaminations. These defects should be completely removed. The depth of defect removal should not exceed 10% of the wall thickness, and the actual wall thickness at the filling removal site should not be less than the wall thickness. The minimum allowable thickness deviation, the clearance should be rounded off
2.The shape of the thread should be kept intact. There must be no drawing, curling or collapse.
3.The inner and outer straight surfaces of internally threaded tubes (including non-sharpened core rods) shall be allowed to have a depth of not more than 4% of the minimum wall thickness and a maximum of 0.2 mm.
4.Other local imperfections that do not exceed the wall thickness to allow negative deviations are allowed to exist.
5.Oxide scales on the inner and outer surfaces of the internally threaded tube should be removed so that the thin oxide layer does not interfere with the inspection.

The grade and chemical composition of steel

Number	Brand	chemical composition(mass fraction)/ %
		C	Mn	Si	Cr	Mo	S	P
1	20G	0.17~0.23	0.35~0.65	0.17~0.37	--	--	≤0.020	≤0.025
2	20MnG	0.17~0.23	0.70~1.00	0.17~0.37	--	--	≤0.020	≤0.025
3	25MnG	0.22~0.29	0.7~1.00	0.17~0.37	--	--	≤0.020	≤0.025
4	12CrMoG	0.08~0.15	0.40~0.70	0.17~0.37	0.40~0.70	0.40~0.55	≤0.020	≤0.025
5	15CrMoG	0.12~0.18	0.40~0.70	0.17~0.37	0.80~1.10	0.40~0.55	≤0.020	≤0.025
Note1:Residual element content of 20G,20MnG,25MnG should satisfy: Cu≤0.20%,Cr≤0.25%,Ni≤0.25%,V≤0.08%,Mo≤0.15%；The remaining elements of other brands should satisfy: Cu≤0.20%,Ni≤0.30%. Note2:The acid soluble aluminum in 20G steel should not be more than 0.010%. Note3:The nitrogen content of the steel produced by the oxygen converter plus the refining of the furnace should not be more than 0.008%.

The size of the internal screw tubes and the allowable deviation of the thread parameters

Code	Project	“A” teeth types allowable deviation	“B” teeth types allowable deviation
A	O.D≤38.1mm 38.1mm＜O.D＜50.8mm 50.8mm≤O.D≤63.5mm O.D≥63.5mm	±0.15mm ±0.20mm ±0.25mm ±0.30mm	--
B	O.D≤38.1mm 38.1mm＜O.D＜50.8mm 50.8mm≤O.D≤63.5mm O.D≥63.5mm	--	±0.15mm ±0.20mm ±0.25mm ±0.30mm
C	I.D of the root of the screw Thread: O.D-(1.11×Minimum W.T×2) O.D≤38.1mm 38.1mm＜O.D＜50.8mm 50.8mm≤O.D≤63.5mm O.D≥63.5mm	±0.15mm ±0.20mm ±0.25mm ±0.30mm	±0.15mm ±0.20mm ±0.25mm ±0.30mm
E	Minimum I.D	Negative deviation to zero	Negative deviation to zero
F	Minimum W.T	+22% 0	+22% 0
G	Thread tips	--	--
I	Thread top width	--	--
	Height of thread: O.D≤38.1mm 38.1mm＜O.D＜50.8mm 50.8mm≤O.D≤63.5mm O.D≥63.5mm	±0.3mm	±0.18mm ±0.20mm ±0.23mm ±0.28mm
K	Side Angle of thread.	±15°	±15°
O	radius of rounded corner at the root of thread	--	--
M	Thread pitch	±3.2mm	±3.2mm
N	Thread lead	±3.2mm×thread tips	±3.2mm×thread tips
	Helix angle	Rating	Rating
T	Thread top width (axial)	±1.3mm	±1.3mm
U	Thread top (axial) groove width	--	--
For the B type, the maximum deviation of any thread height can exceed the allowable deviation specified in the table, but it should not exceed the allowable deviation of 0.08mm, and the average height of all threads should be in line with the given deviation range. The rating is based on the axis of the pipe.

Who We are ?

-------A professional steel pipes materials inventor, manufacturer and solution provider
Torich International Limited is a professional manufacturer and exporter of steel pipes materials. It is an international marketing and sales company specialized in steel tubes, which holds the factories of Seamless Steel Tubes with Carbon and Alloy Steel Grade, Welded Precision Steel Tubes,DOM Steel Tubes, Seamless & Welded Stainless Steel Tubes with Nickel and Alloy Steel Grade.
Our factory was established since 1997, with the name of TORICH INTERNATIONAL LIMITED. The factories’ technicians are of great engineering experience in steel pipe industry for more than 20 years, which are in great command of production technology for Cold Drawing and Cold Rolling. So we have strong technician team and manufacturing capability.

What products we do?

------- Invent and produce various Precision Steel Pipes

Our steel pipes cover the following ranges:
Seamless Precision Steel Pipes

Bearing Steel Tubes
Welded Precision Steel Pipes, with DOM production
Seamless Heat Exchanger Steel Pipe
Seamless Boiler Steel Pipes

Honed Tubes

Hydraulic Cylinder Steel Tubes

Hydraulic Telescopic Cylinder Tubes
Seamless Structural Steel Pipes
Seamless Mechanical Steel Pipes
Seamless Alloy Steel Tubes & Pipes
Seamless Stainless Steel tubes
Welded Stainless Steel Tubes
Seamless Stainless Steel Tubes & Pipes
Welded Stainless Steel Tubes & Pipes
Seamless Carbon Steel Tubes & Pipes
Nickel Alloy Steel Tubes & Pipes

What TORICH do:
1. Producing Steel Tubes
2. Selling both on Domestic and International Market
3. Precisely Targeting Customers’ Requirement- Sourcing the right factory for right products for Customers

Products Application:
Oil Cylinders
Air Cylinder, 
Automotive Cylinder Liners
Boilers, Pressure Vessels
Shell & Heat Exchangers
Jack Lifting
Telescopic Systems
Pneumatic Cylinders
Agricultural Machineries

Size range is: 
O.D. 4-350mm, 
W.T. 0.5-30mm, 
Length: according to customer’s requirement and agreement
 

Steel Grade:
Carbon Steel Grade:
ST35.8, ST37.0, ST44, ST52;
E155, E195, E215, E235, E275, E355;
195GH, P235GH, P265GH, P195TR1, P195TR2, P235TR1, P235TR2, P265TR1, P265TR2;
SAE1010, SAE1020, SAE1026, SAE1035, SAE1045;

Carbon steel tube: SA178, A179, A192, A210, SA213, SA214, etc.
Alloy Steel Grade:
T2, T5, T9, T11, T12, T17, T21, T22, T91,T92, 15Mo3,16Mo3, 13CrMo44;
SAE4130, SAE4140, 40Cr, 40Cr4, 10CrMo910, 12CrMo910, 11CrMo910,
25CrMo4, 35CrMo, 35CrMo4, 42CrMo4, 34CrMo4, 20MnV, 20MnV6,20CrMn;
Carbon steel tube: A179,A192,A210,DIN17175,etc.

Bearing Steel Grades:
GCr15 52100 suj2 suj3 100Cr6 SKF3S SKF3S 20CrNiMo 8620H 4118H;

Nickel Alloy Grade:
N02200/2201, N04400, N06600, N06601, N06625, N06852, N06219, N06690, N08800/8810/8811, N08825, N08028, N08535, N08904, N08925, N08926, N010276, N06022, etc.

Austenitic/Super Austenitic Stainless Steel Grade:
304/304L, 316/316L, 314, 321, 347H, 316Ti, 316LMod, 317L/N, 310S, 253MA, 330, 904L, S31254, XM-19, etc. 

Ferrite/Martensite Stainless Steel Grade:
TP410, TP405, TP420, TP430, TP430Ti, TP403, TP409, TP444, TP439, TP446, etc. 

Duplex/Super Duplex Stainless Steel Grade:
S31803, S32304, S31500, S32550, S32750, S32760, etc. 
Corporate Culture:
We focus on Quality First, Quality Traceability, and Quality Stability!
We focus on Customer First, People First, and Quality-Oriented!
Success:
First factory started in 1997, in the name of Torich , now covers 50000 square meters of factory building, with more than 100employees, and over 45 million RBM assets.
In 2008, we started the company of Torich International Limited for international business and marketing.
Welcome partners from all over the world for long term cooperation!