DIN 17175 Seamless Steel Tubes For Elevated Temperatures
 
 
Scope
This standard applies to seamless steel pipes. These pipes can be used to manufacture steam boilers, pipes, pressure vessels and instruments operating at temperatures up to 600 ° C and at high temperatures. Due to the total load and special oxidation conditions, these pipes can be lowered or raised. High listed temperature limits.
 
 
The same effective standards and reference materials
DIN 2391, part 1 , cold drawn or cold rolled precision seamless steel: size.
DIN 2413, Steel tube: Wall thickness resistance to internal pressure.
DIN 2448, seamless steel pipe: size and weight.
DIN 2915, seamless and welded steel tubes for water tube boilers.
DIN 2917 , Non-stitched steel tubes for hot steam pipes and headers : Dimensions
DIN 17007 Part 2
DIN 50049, material test certificate
DIN 50115, Metal Materials Experiment: Notch Impact Toughness Test
DIN 50125, Metallic Materials Experiment: Tensile Test, Preparation Principles
DIN 50136, Metallic Materials Experiment: Ring-shaped flattening test of pipe
DIN 50137, steel test: ring flaring test of pipe
DIN 50138, steel test: ring tensile test of pipe
DIN 50140, Metallic Materials Test: Tube and Tube Tension Tests for Incompetent Adjustability Meters
DIN 50145, Metal Materials Experiment: Tensile Test
 
 
Concept
As far as this standard is concerned, steels that have a good mechanical properties at a higher temperature, up to 6 00 °C, and even under long-term load, are called heat-strength steels.
 
 
Marking and ordering
The steel grade or material number should be written to the abbreviation of the product as shown in the following example:
Example 1:
A DIN 17175 outer diameter 3 8mm, wall thickness 2.5 mm mm steel grade ST35.8 material, number 1.03 0 5 seamless steel pipe whose name is written: steel pipe DIN 17175-ST35.8 - 38 × 2.5 or steel pipe DIN 17175 -1.0305 - 3 8 × 2 . 5
 
When ordering goods, except for the above-mentioned requirements, the total length required and the required acceptance test certificate should be stated. If it is a non-incorporated steel pipe, the quality level should be stated.
 
 
Requirements
Production method
The steel pipe to which this standard relates may be produced by hot rolling, cold rolling, hot pressing, hot drawing or cold drawing.
The tube steel can be smelted in a flat furnace or an electric furnace according to the oxygen blowing method, and all steels should be cast in a static manner.
 
 
Supply status
The full length of the steel pipe shall be delivered through a suitable heat treatment. According to each steel type, heat treatment includes:
- normal fire
- Retirement
- tempering; from the quenching temperature, it is not cold, but then tempered
as well as
- Adjust the mass by the isothermal transformation method.
If a satisfactory uniform crystal structure is produced after hot work, the appropriate heat treatment for St35.8, St45.8, 17Mn4, 19Mn5, and 15 Mn3 steels is considered to have been met. Under the same premise, the 13CrMo44 and 10CrMo910 steels will be tempered to replace the complete quenching and tempering treatment. In any case, 14MoV63 and 20XcrMoV121 steels are supplied after tempering treatment.
 
 
Chemical composition of DIN 17175 Seamless Steel Tubes
 

Standard	grade	Chemical composition
		C	Si	Mn	P、S	Cr	Mo
DIN 17175	St35.8	≤0.17	0.10-0.35	0.40-0.80	≤0.030	/	/
	St45.8	≤0.21	0.10-0.35	0.40-1.20	≤0.030	/	/
	15mo3	0.12-0.20	0.10-0.35	0.40-0.80	≤0.030	/	0.25-0.35
	13CrMo44	0.10-0.18	0.10-0.35	0.40-0.70	≤0.030	0.70-1.10	0.45-0.65
	10CrMo910	0.08-0.15	≤0.50	0.40-0.70	≤0.030	2.00-2.50	0.90-1.20

 
 
Mechanical property of DIN 17175 Seamless Steel Tubes
 

Standard	grade	Tensile Strength(MPa)	Yield Strength(MPa)	Elongation(%)
DIN 17175	St35.8	360-480	≥235	≥25
	St45.8	410-530	≥255	≥21
	15mo3	450-600	≥270	≥20
	13CrMo44	440-590	≥290	≥20
	10CrMo910	450-600	≥280	≥18

 
 
Process performance
The tube should meet the requirements of the ring test. For the expansion rate (diameter change) of the ring-shaped flaring experiment, no impermissible defects (such as cracks, crepe, folding, and delamination) shall occur during the test.
 
 
Surface condition
The tube must have a manufacturing method that achieves a relatively smooth inner and outer surface, so that it is possible to use either a hot rolling method or a cold rolling method. Tubes should not have unacceptable cracks, creases and folds. As long as the wall thickness of the steel pipe does not exceed the allowable dimensional deviation, and does not affect the performance of the steel pipe, it is permissible to create some uneven and shallow longitudinal scratches during the manufacturing process. Mechanical machining (such as buffing) can be used to remove the slight subsidence of the surface, but not to reduce the minimum allowable wall thickness.
 
 
Dimensions Tolerance

Project	Standard		Size range		Tolerance
Outer diameter	DIN17175		Hot rolled steel pipe	OD ≤ 100mm	± 0.75%( Min ± 0.5mm )
				OD＞ 100~ 320mm	± 0.9%
			Cold drawn steel pipe OD ≤ 120mm		± 0.6%( Min ± 0.25mm )
Wall thickness	DIN17175	OD ≤ 130mm	WT ≤ 2Sn		+15%~-10%
			WT ＞ 2Sn~4Sn		+12.5%~-10%
			WT ＞ 4Sn		± 9%
		130 ＜ OD ≤ 320mm	WT ≤ 0.05OD		+17.5%~-12.5%
			0.05OD ＜ WT ≤ 0.11OD		± 12.5%
			WT ＞ 0.11OD		± 10%

 
 
Heat treatment and processing
Reference data for heat treatment temperature
Hot working is possible from 1100 to 80 ° °C, and the temperature can be reduced to 750 °C during processing.
In the matching-correction work of the local department, attention should be paid to the effective specification of hot work; there should be a supervisory temperature system. In the higher temperature range, ie 1100 to 900 °C, it is suitable for forging and pier thickening, about 85 °C, and the temperature can be lowered to above 75 °C during the processing.
For example, before the last process, or during the same hot working process, if the heating temperature of the workpiece is above the normalizing temperature but not more than 1000 ° C, and the deformation process is above 75 ° C, or ———— In the last process, the degree of deformation does not exceed 5% - at the end of 7 00 °C, then the normalizing of the St35.8, St45.8, 17Mn4, 19Mn5, and 15Mo3 steels is superfluous. The 13CrMo44 and 10CrMo910 only need to be tempered.
For multiple times and/or long time heat treatments at temperatures around 1000 to 1000 °C, the workpiece should be cooled to around 350 °C before the last deformation process. If the normalizing or quenching and tempering treatment is more than enough, then the temperature at which the steel is hot-worked should not exceed 1 000 °C.
Conversely, if the molding end temperature is above 10 °C, then the St35.8, St45.8, 17Mn4, 19Mn5, and 15Mo3 steels must be normalized, while the 13CrMo44 and 10CrMo910 should be tempered.
14MoV63 and X20CrMoV121 steels should be reconditioned after hot work.
 
Pipes made of steel according to this standard may be cold-worked, such as pipe bending, flaring, drawing and pipe cutting; for X20CrMoV121 and 14CrV63 steels, the high yield point and tensile strength shall be noted. After bending, expanding, and cold drawing with normal deformation, there is no need to supplement the heat treatment.
 
 
Original material test
  A thin sheet should be taken at the top end of each round or square bar ingot for a pickling test to determine if the top end is adequately cut. Ultrasonic testing can also be performed on the shrinkage hole as selected by the supplier.
 
 
Test:
Chemical composition verification test
hydrostatictest
Tensile test
Notched impact test
Yield strength test
Ring test
Nondestructive testing
 
 
Tube flag
All steel pipes submitted for testing and acceptance shall be marked on the left and right sides of the pipe end at 300 mm. The mark is usually a number. Thin-walled tubes can also be used in other forms.