3. Stick electrodes for welding of heat resistant and high temperature steels

Transcription

1 3. Stick electrodes for welding of heat resistant and high temperature steels Part number 4936 B 4948 B E B E NiCrFe 3 82 R B E NiCrMo 3

2 Stick electrodes for welding of heat resistant and high temperature steels Heat resistant steels are mainly used for components which are subject to operating temperatures of opprox. 350 C to 540 C. They are alloyed mainly with chrome and molybdenum and sometimes with Vanadium and have the required long term heat resistant properties for this temperature range. Up to 540 C these qualities scarcely oxidize. If additional non-scaling properties beyond 540 C are required, 12% Chrome Steels with additives of Molybdenum, Vanadium and Niobium and Tantalum should be considered. At temperatures over 600 C behaviour under long period stressing tapers off so significantly in heat-treatable steels that austenitic Chrome-Nickel Steels must be used. The basic type of this steel contains 16% Chrome and 13% Nickel with Molybdenum, Niobium, and Tantalum as additives to improve long period stressing. For nuclear reactor construction the steel X6CrNi is particularly significant. Stable austenitic steels are welded to produce improved heat resistant properties in the solution heat treatment state. The temperature during the welding process asolutely must be kept low because of hot crack susceptibility. Heat accumulation through local overheating (minimal thermal conductivity) is to be avoided. Hence only small diameter electrodes should be used (stroke pass welding). Generally welding is carried out without preheating. For larger wallthickness preheating to 100 C-200 C is advisable; temperature of between-layer should be at 150 C.

3 4936 B DIN 8575 CrMoWV12 B To weld on high temperature 12% chromium alloys of the same or similar quality which can be hardened and tempered at operating temperatures up to 600 C. Preheating and intermediate layer temperature C. After welding low air cooling to C. Then temper annealing 4h C furnace cooling. C Si Mn Cr Ni Mo V W 0,16 0,3 0,5 11 >1,0 >1,0 0,3 0,5 (filier metal at 20 C) Minimum values after temper annealing at 760 C 0.2 limit 580 N/mm ² Yield point N/mm ² Tensile strength 680 N/mm ² Elongation after fracture 15 `)/0 Notched bar impact work 45 J (ISO-V) Martensite, can be hardened and tempered, free from ferrite DIN designation X20CrMoV X22CrMoV X21CrMoV G-X22CrMoV X20CrMoWV

4 B E DIN 8556 E 19 9 B AWS E Special electrode to weld on high temperature alloys of the same/a similar quality. High temperatures up to 650 C, scale resistant up to 750 C. The weld material has good resistance to embrittlement tendencies. Preheating: High temperature steels of the same quality none. Heat treatment: 1 h 900 C, cool down slowly. C Si Mn Cr Ni Mo <0,06 0,3 1,3 19 9,5 (filier metal at 20 C) Minimum values welding condition 0.2% nonproportional elongation 320 N/mm ² 1.0% nonproportional elongation 340 N/mm ² Tensile strength 500 N/mm ² Elongation after fracture 35 % Notched bar impact work 80 J (ISO-V) Austenite with approx. 5% ferrite DIN designation X6CrNi

5 82B E NiCrFe 3 82R 140 DIN 1736 E NiCr 19 Nb AWS E NiCrFe 3 To weld on high temperature steels/cast steel grades and Ni-base alloys, high temperature. Stainless, also suitable for austenite-ferrite compounds. C Si Mn Cr Ni Mo Nb <0,05 <0,9 3,5 19 > 67 1,0 2,5 (filler metal at 20 C) Minimum values welding condition 0.2% nonproportional elongation 380 N/mm ² 1.0% nonproportional elongation 400 N/mm ² Tensile strength 600 N/mm ² Elongation after fracture 30 % Notched bar impact work 80 J (ISO-V) Austenite, free from ferrite DIN designation NiCr20Ti NiCr20TiAl NiCr23Fe

6 625 B E NiCrMo 3 DIN 1736 E NiCr 20 Mo 9 Nb AWS E NiCrMo 3 High temperatures up to 1000 C. To weld on high temperature steels of the same/a similar quality. C Si Mn Cr Ni Mo Nb Fe <0,04 0,5 1,0 21 >60 9 2,5 <3 (filler metal at 20 C) Minimum values welding condition 0.2% nonproportional elongation 420 N/mm ² 1.0% nonproportional elongation 440 N/mm ² Tensile strength 720 N/mm ² Elongation after fracture 30 % Notched bar impact work 60 J (ISO-V) Austenite DIN designation NiCr28Mo9Nb Inconel Incoloy