DIN 17 861

Din Standard 17861The DIN 17861 Standard provides the technical delivery conditions for the manufacture and supply of Seamless Circular Titanium and Titanium Alloy Tubes. This guides provides an overview to the key areas of the standard.

Overview

The standard covers titanium and titanium alloy bars making the distinction between CP Titanium and Low Alloy Titanium tubes used in chemical plant and industrial applications where the anti-corrosiveness of the metal is required against High Alloy Titanium tubes used primarily for the low mass and non magnetic properties and so used in advanced engineering, tooling etc. The standard does not cover the use of titanium tubes in aerospace applications, instead references the standard DIN 65 039. The standard only also cover circular tubing profiles. Finally the standard details a two class testing approach with the second class being a more comprehensive approach.

Ordering Information

When ordering material under the DIN 17861 a formal specification approach is outlined with an essential or optional specification being used. A standard designation outlines the product definition and includes the following information:

  • The name of the product i.e. Titanium Tube
  • The DIN Number production conforms to i.e. DIN 17 861
  • Product Dimensions i.e. External Diameter, Wall Thickness, NPS Size, Length
  • Titanium Grade as denoted by the designation name or number from the table 1 of the standard
  • Supply condition symbol e.g. b

Essential Ordering Information

As per the DIN 17861 standard the standard way that titanium tubes should be specified includes the following:

  • Quantity of tubes (e.g. in meters of pcs)
  • The name of the product i.e. Titanium Tube
  • The DIN Number production conforms to i.e. DIN 17 861
  • Product Dimensions i.e. External Diameter, Wall Thickness, Length from the table 5 of the standard
  • Titanium Grade as denoted by the designation name or number from the table 1 of the standard
  • Supply condition number
  • Test class
  • Inspection Document required
  • For 3rd Party Inspections the Agency to use

Optional Ordering Information

As per the standard there a number of additional ordering requirements to be met:

  • Manufacturing Processes
  • Chemical Composition
  • Dimensions outside of those specified in the standard
  • The proof strength differences at ambient temperatures
  • Requirements for tightness testing
  • Non-destructive testing requirements
  • Testing observation requirements
  • Continuous Markings

Titanium Requirements

The section covers the requirements for the manufacturing processes to be followed, the chemical composition to be achieved along with the mechanical properties, dimensions and tolerances, material conditions and tightness.

Chemical Compositions

The chemical compositions to be achieved, referred to as the Ladle Analysis at each grade is by reference to the standards DIN 17 850 (Titanium) and DIN 17 851 (Titanium Alloys). The table below introduces the typical grade ranges.

MaterialChemical Composition (%)
Fe* maxO maxN maxC maxH** maxOthersTi
Single maxTotal Max
Ti10.150.120.050.060.0130.100.40Remainder
Ti20.200.180.050.060.0130.100.40
* For tubes to be used in applications in corrosive environments the Fe content should be no more than 0.15
** For the tubes less than 2mm in thickness the maximum hydrogen content is 0.015.

Mechanical Properties

The mechanical properties of the titanium tubes are required to meet the following mechanical properties at an ambient temperature with wall thickness’s to 12.5mm

MaterialMinimum 0,2%
proof strength*,
Rp 0,2 in N/mm2
Minimum 1%
proof strength*,
Rp 1,0 in N/mm2
Tensile Strength,
Rm, in N/mm2
Minimum elongation
at fracture, A5,
longitudinal, as a
percentage
DesignationNumber
Ti13.7025180200290 to 41030
Ti23.7035250270390 to 54022
Ti33.7055320350460 to 59018
Ti1Pd3.7225180200290 to 41030
Ti2Pd3.7235250270390 to 54022
Ti3Pd3.7255320350460 to 59018
TiNi0,8Mo0,33.7105345370min 48018
TiAl6V43.7165830Unspecifiedmin 90010
TiAl3V2,53.7195520min 62015**
TiAl6V6Sn23.7175930min 10008
* The 1% proof strength is required by default with the 0,2% proof strength required on specification
** For wall height of 1mm and below the A5 is 12%

For elevated temperatures the following minimum values are:

MaterialMinimum 1% proof strength, Rp1,0 in N/mm2
at a temperature in C of
DesginationNumber75100150200250300
Ti1
Ti1 Pd
3.7025
3.7225
19518015011090
Ti2
Ti2Pd
3.7035
3.7235
255235195145115105
Ti3
Ti3Pd
3.7055
3.7255
300275220165130115

Dimensions and Tolerances

The DIN 17861 Standard defines a set of preferred dimensions with appropriate wall thicknesses for given Outside Diameters with specifications outside of the ranges to be subject ordering. The standard also defines an acceptable mass range is defined in terms of an equation and also against the list of preferred dimensions. For tolerances the following are to be followed:

Outside Diameter and Wall Thickness Tolerances

The table below details out the permissible Outside Diameter and Wall Thickness Tolerances according the standard DIN 17 861.

Manufacturing
Process
Limit Deviation of
Outside Diameter da
Wall thickness, s
s:da
ratio
Limit Deviations
OverUp to
Cold Formed+/- 0,5% but at least +/- 0,1mm+/- 10% but at least +/- 0,2mm
Hot Formed+/-1 % but at least +/- 0,5mm0,100+/- 10%
0,0500,100+/- 12,5%
0,0250,050+/- 15%
0,025+/- 20,0%

Length Tolerances

The table below details out the permissible tube length tolerances according the standard DIN 17 861.

Type of LengthOutside DiameterLengthLimit Deviations
OverUp toOverUp to
As Manufactured LengthAll Types20007000Not Specified
Specified LengthAll TypesSubject To Agreement+/- 500
401000+1
0
10002000+2
0
20003000+3
0
30004000+4
0
4000+5
0
401686000+5
0
6000+10
0
168+10
0

Supply Preparation and Surface

The table below details out the differing processing and supply approaches according the standard DIN 17 861 which are to be state during ordering.

Conditions
on Supply (symbol)
Types of TreatmentSurface Appearance
a1Hot Formed, Not Heat Treated, Not DescaledOxidised
a3Hot Formed, Not Heat Treated, DescaledBright (Descaled)
bHot Formed, Heat Treated, Not DescaledOxidised
c1/c2Hot Formed, Heat Treated, Descaled (mechanically
or my means of blasting and/or pickling)
Bright
gCold Formed, heat treated in oxidic atmosphereBright (Heat Treated)
hCold Formed, heat treated in oxidic atmosphere, descaled
(mechanically or by means of blasting and/or pickling)
Bright (Descaled)
mCold formed, heat treated in inert gas or under vacuumBright (Descaled)
oPolished externallyBright (Polished)
Normal heat treatment parameters: electric/gas-fired furnace, oxidic atmosphere, inert gas or vacuum

Testing Scope and inspection documents for the Test Classes 1 and 2

The different classes of testing and the respective testing to be carried out for each is outlined in the table below.

NoTest to be Carried outAs in
Subclause
Scope of TestingDIN 50 049
Inspection Document*
Test Class 1Test Class 2
1Ladle Analysis4.4.11 analysis per castInspection Certificate B
2Product Analysis4.4.11 analysis per cast
3Determination of H2 Content4.4.11 determination per cast or heat
treatment batch
4Tensile Test at Ambient
Temperature
4.4.21 test piece taken from 1 test tube,
per batch
Inspection Certificate A, B
or C or inspection report
5Tensile Test at elevated
Temperature
4.4.31 test piece per
cast and size
6Flattening Test4.4.41 test piece taken from 1 test tube,
per batch
Drift or ring expanding test4.4.5
4.4.6
CF table 8
7Tightness test4.4.7All tubesInspection Certificate B
8Non-destructive test for
laminations
4.4.8All tubes where s is
over 3,6mm
Inspection Certificate B
9Non-destructive test for
longitudinal imperfections
4.4.8All Tubes
10Non-destructive test for
traverse imperfections
4.4.8
11Visual Check4.4.9All tubesInspection certificate A,B or C
or inspection report
12Check for dimensional Accuracy4.4.10All tubes
* in accordance with DIN 50 049, the following parties are responsible for testing
inspection certificate A: the inspector named in the official regulations
inspection certificate B: the works inspector
inspection certificate C: the purchaser’s authorised representative;
inspection report: Both the purchaser’s authorised representative and the works inspector.