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Stainless Steel 314 - 1.4841

This data sheet applies for hot and cold rolled sheet, strip and bars, semi-finished products, rods and sections.

Application

For construction parts which should be resistant to scaling up to about 1150 °C. The resistance to oxidising and reductive sulphurous gases is low; to carbonising gases, especially over 900°C as well.

Chemical Compositions*

Element % Present (in product form)
Carbon (C) 0.20
Silicon (Si) 1.50 - 2.50
Manganese (Mn) 2.00
Phosphorous (P) 0.045
Sulfur (S) 0.015
Chromium (Cr) 24.00 - 26.00
Nickel (Ni) 19.00 - 22.00
Nitrogen (N) 0.11
Iron (Fe) Balance
*Maximum value unless otherwise stated

Mechanical properties (at room temperature in annealed condition)

Product Form
C, H, P L
Thickness a or diameter d (mm) a ≤ 12 d ≤ 25
Proof Strength Rp0.2 N/mm2 230
Rp1.0 N/mm2 270
Tensile Strength Rm N/mm2 550 - 750
HB. Max 1)2)3) 223
1) The maximum HB values may be raised by 100 units or the maximum tensile strength value may be raised by 200 N/mm2 and the minimum elongation value be lowered to 20% for cold worked sections and bars of ≤ 35mm thickness.
2) For guidance only.
3) For rod, only the tensile values apply.

Reference data on some physical properties

Density at 20°C kg/m3 7.9
Thermal Conductivity W/m K at 20°C 15
500°C 19
Specific Thermal Capacity at 20°C J/kg K 500
Electrical Resistivity at 20°C Ω mm2/m 0.9
Coefficient of linear thermal expansion 10-6 K-1 between 20°C and 200°C 15.5
400°C 17.0
600°C 17.5
800°C 18.0
1000°C 19.0

Processing / Welding

Standard welding processes for this steel grade are:

  • TIG-Welding
  • MAG-Welding Solid Wire
  • Arc Welding (E)
  • Laser Bean Welding

Preheating is not necessary for this steel. Interpass temperature should not exceed 150°C. Heat treatment after welding is normally not usual. Austenitic steel have only 30% of the thermal conductivity of non-alloyed steels. Their fusion point is lower than that of non-alloyed steels, therefore austenitic steels have to be welded with lower heat input than non-alloyed steels. To avoid overheating or burn-through of thinner sheets, higher welding speed has to be applied. Copper back-up plates for faster heat injection are functional, whereas, to avoid cracks in the solder metal, it is not allowed to surface-fuse the copper back up plate. This steel has an extensively higher coefficient of thermal expansion as non-alloyed steels. In connection with a worse thermal conductivity, a greater distortion has to be expected. When welding 1.4841 all procedures, which work against this distortion (e.g. back-step sequence welding, welding alternately on opposite sides with double-V butt weld, assignment of two welders when the components are accordingly large) have to be respected notably. For product thicknesses over 12mm the double-V butt weld has to be preferred instead of a single-V butt weld. The included angle should be 60 - 70°, when using MIG-welding about 50° are enough. An accumulation of weld seams should be avoided. Tack welds have to be affixed with relatively shorter distances from each other (significantly shorter than these of non-alloyed steels), in order to prevent strong deformation, shrinking or flaking tack welds. The tacks should be subsequently grinded or at least be free from crater cracks. 1.4841 in connection with austenitic weld metal and too high heat input the addiction to form heat cracks exists. The addiction to heat cracks can be confined, if the weld metal features a lower content of ferrite (delta ferrite). Contents of ferrite up to 10% have a favourable effect and do not affect the corrosion resistance generally. The thinnest layer as possible have to be welded (stringer bead technique), because a higher cooling speed decreases the addiction to hot cracks. A preferably fast cooling has to be aspired to while welding as well, to avoid the vulnerability to intergranular corrosion and embrittlement. 1.4841 is very suitable for lser beam welding. With a welding groove width smaller 0.3mm respectively, 0.1mm product thickness the use of filler metals is not necessary. With larger welding grooves a similar filler metal can be used. With avoiding oxidation within the seam surface laser beam welding by applicable backhand welding, e.g. Helium as inert gas, the welding seam is as corrosion resistant as the base metal. A hot crack hazard for the welding seam does not exist, when choosing an applicable process. 1.4841 is also suitable for laser beam fusion cutting with nitrogen or flame cutting with oxygen. The cut edges only have small heat affected zones and are generally free of micro cracks and thus is well formable. While choosing an applicable process the fusion cut edges can be converted directly. Especially, they can be welded without any further preparation. While processing only stainless tools like steel brushes, pneumatic picks and so on are allowed, in order to not endanger the passivation. It should be neglected to mark within the welding seam zone with oleaginous bolts or temperature indicating crayons. For cleaning the surface the processes brushing, grinding, pickling or blasting (iron-free silica sand or glass spheres) ca be applied. For brushing only stainless steel brushes can be sued. Pickling of the previously brushed seam area is carried out by dipping and spraying, however, often pickling pastes or solutions are used. After pickling a careful flushing with water must be done.

Remark

In quenched condition the material can be slightly magnetizable. With increasing cold forming the magnetizability increases.

Editor

thyssenkrupp Materials (UK) Ltd
Cox’s Lane
Cradley Heath
West Midlands
B64 5QU

Important Note

Information given in this data sheet about the condition or usability of materials respectively products are no warranty for their properties, but act as a description. The information, we give on for advice, comply to the experiences of the manufacturer as well as our own. We cannot give warranty for the results of processing and application of the products.

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