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| For the Urea / Fertilizer Industry . Material No. 1.4417 |
Steel material No. DIN 1.4417 is a ferritic-austenitic chromium-nickel-molybdenum steel of increased yield point and increased resistance againststress corrosion.
1. Material description X2 CrNiMoSi 2 5-7-3
Material No. 1.4417
ASTM A 669
Equivalent SANDVIC 3RE60
2. Supply form and condition seamless tubes, annealed
3. Range of dimensions (Tubes) Outside Diameter: . . .10-50 mm
Wall Thickness: ...... ...... ...... ...... ...... ...... . .1-4 mm
Length: ...... ...... ...... ...... ...... ...... . . .max. 12.5 mm
(depending on diameter and wall)
4. Physical properties
Density 7.7 g/cm2
Electrical resistance 0.25 Ohm mm2/m
Thermal conductivity at 20°C 20.9 W/m°C
at 300°C 25.5 W/m°C
Linear coefficient of at 20-100°C 11.2 10 6 m/m °C
expansion at 20-200°C 13.0 10 6 m/m °C
at 20-300°C 13.6 10 6 m/m °C
at 20-400°C 14.2 10 6 m/m °C
Modulus of elasticity at 20°C 198 10 3 m/m °C
at 250°C 174 10 3 m/m °C
at 300°C 169 10 3 m/m °C
5. Heat treatment
Quench annealing 950-1050°C/air or water
6. Welding
Weldability of Material No. 1.4417 is good. Due to the danger of carburizing, gas fusion welding should be avoided. For wall thicknessfrom 0.8 mm up TIG-welding is recommended; from 1.5 mm up especially in case of fillet welds-arc welding with sheated barelectrodes is possible. After welding no heat treatment is required.For the design of heat exchangers, tubes of Material No. 1.4417 are normally connected with tubes (pipes) sheets of fully austenitic steel orboiler construction steel. For these cases the following welding filler metals may be recommended:
a. to austenitic steel, e.g. (1.4571
Nominal analysis
20% Cr 67 % Ni 3 % Fe
19% Cr 10 % Ni 2.5 % Mo
19% Cr 11.5 % Ni 2.8 % Mo
b. to low-alloyed steel, e.g. boiler plate 17Mn4
Nominal analysis
24 % Cr 13 % Ni
20 % Cr 67 % Ni 3 % Fe
18 % Cr 8 % Ni 6 % Mn
The welding filler metals mentioned under a. and b. have a C-content of max. 0.03% with the exception of alloy-type 18/8/6 having aC-content of approx 0.10%. If high stress of the welding joints has to be taken into account, welding filler metals of LC-quality shouldbe used. In case of using Mo-free filler metal, the corrosion characteristics of the weld metal have to be taken into account.
7. Cold bending
Generally, in case of usual bending radii, post heating will not be required. In case of a higher degree of deformation at lowtemperatures ( > 10% ) annealing as indicated under 7. is necessary.
8. Hot bending
Hot bending should be performed in the temperature range from 1100-900°C. Afterwards, quench annealing as described under 7. willhave to be carried out.
9. Corrosion behaviour
Due to its two-phase structure, Material No. 1.4417 has a higher resistivity against stress corrosion cracking than comparable fullyaustenitic CrNi-steels. Its use in media containing chloride, e.g. brackish water, is to be recommended, when austenitic steels havefailed because of stress corrosion cracking. Its resistance against pitting is similar to that of X2CrNiMo 1812. In non-oxidizing solutions,e.g. formic acid and oxalic acid, a good continuity is noted.
10. Application
Due to its favourable physical-technological and corrosion-chemical characteristics, Material No. 1.4417 is preferably used in thefollowing fields:
High pressure processes of the chemical industry
Due to its increased yield point there are advantages regarding wall thickness design. |
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