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.

Material Chemical Composition (%)
Fe* max O max N max C max H** max Others Ti
Single max Total Max
Ti1 0.15 0.12 0.05 0.06 0.013 0.10 0.40 Remainder
Ti2 0.20 0.18 0.05 0.06 0.013 0.10 0.40
* 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

Material Minimum 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
Designation Number
Ti1 3.7025 180 200 290 to 410 30
Ti2 3.7035 250 270 390 to 540 22
Ti3 3.7055 320 350 460 to 590 18
Ti1Pd 3.7225 180 200 290 to 410 30
Ti2Pd 3.7235 250 270 390 to 540 22
Ti3Pd 3.7255 320 350 460 to 590 18
TiNi0,8Mo0,3 3.7105 345 370 min 480 18
TiAl6V4 3.7165 830 Unspecified min 900 10
TiAl3V2,5 3.7195 520 min 620 15**
TiAl6V6Sn2 3.7175 930 min 1000 8
* 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:

Material Minimum 1% proof strength, Rp1,0 in N/mm2
at a temperature in C of
Desgination Number 75 100 150 200 250 300
Ti1
Ti1 Pd
3.7025
3.7225
195 180 150 110 90
Ti2
Ti2Pd
3.7035
3.7235
255 235 195 145 115 105
Ti3
Ti3Pd
3.7055
3.7255
300 275 220 165 130 115

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
Over Up to
Cold Formed +/- 0,5% but at least +/- 0,1mm +/- 10% but at least +/- 0,2mm
Hot Formed +/-1 % but at least +/- 0,5mm 0,100 +/- 10%
0,050 0,100 +/- 12,5%
0,025 0,050 +/- 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 Length Outside Diameter Length Limit Deviations
Over Up to Over Up to
As Manufactured Length All Types 2000 7000 Not Specified
Specified Length All Types Subject To Agreement +/- 500
40 1000 +1
0
1000 2000 +2
0
2000 3000 +3
0
3000 4000 +4
0
4000 +5
0
40 168 6000 +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 Treatment Surface Appearance
a1 Hot Formed, Not Heat Treated, Not Descaled Oxidised
a3 Hot Formed, Not Heat Treated, Descaled Bright (Descaled)
b Hot Formed, Heat Treated, Not Descaled Oxidised
c1/c2 Hot Formed, Heat Treated, Descaled (mechanically
or my means of blasting and/or pickling)
Bright
g Cold Formed, heat treated in oxidic atmosphere Bright (Heat Treated)
h Cold Formed, heat treated in oxidic atmosphere, descaled
(mechanically or by means of blasting and/or pickling)
Bright (Descaled)
m Cold formed, heat treated in inert gas or under vacuum Bright (Descaled)
o Polished externally Bright (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.

No Test to be Carried out As in
Subclause
Scope of Testing DIN 50 049
Inspection Document*
Test Class 1 Test Class 2
1 Ladle Analysis 4.4.1 1 analysis per cast Inspection Certificate B
2 Product Analysis 4.4.1 1 analysis per cast
3 Determination of H2 Content 4.4.1 1 determination per cast or heat
treatment batch
4 Tensile Test at Ambient
Temperature
4.4.2 1 test piece taken from 1 test tube,
per batch
Inspection Certificate A, B
or C or inspection report
5 Tensile Test at elevated
Temperature
4.4.3 1 test piece per
cast and size
6 Flattening Test 4.4.4 1 test piece taken from 1 test tube,
per batch
Drift or ring expanding test 4.4.5
4.4.6
CF table 8
7 Tightness test 4.4.7 All tubes Inspection Certificate B
8 Non-destructive test for
laminations
4.4.8 All tubes where s is
over 3,6mm
Inspection Certificate B
9 Non-destructive test for
longitudinal imperfections
4.4.8 All Tubes
10 Non-destructive test for
traverse imperfections
4.4.8
11 Visual Check 4.4.9 All tubes Inspection certificate A,B or C
or inspection report
12 Check for dimensional Accuracy 4.4.10 All 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.