Two welding processes were selected for the investigation of weld repair procedures without pwht. Where an aws classification is shown, specific con. The postheat temperature may be the same as, or greater than, the original preheat temperature specified. P91 to p91 this procedure employed dual process welding involving a root layer and three hot runs deposited using the manual tungsteninert gas tig welding process, followed by filling and capping using the submerged arc welding process. This vnbb microalloyed steel benefits from precipitation strengthening due to mxtype and m23c6type precipitation which occurs during the tempering cycle. Summary of welding procedures used during pipes welding by e9015b9er90sb9. Welding research introduction grade 91 steel, known as the modified 9cr1mov, designated as p91 for pipe and plate astm a335 p91, and t91 for tube astm a2 t91, is a creepenhanced ferritic steel that has been widely used in powergenerating applications as a header, superheater, and reheater. Bohler weldingconsumables for thermal power stations 5 mild steels bohler standard en aws welding process typical analysis % typical mechanical properties sizes mm characteristics and applications smaw c 0. Material and method in the present work, it was used a p91 seamless pipe in the normalized and tempered condition, with 152 mm outside diameter and a wall thickness of 18 mm. However a straight change from grade91 to carbon steel is a bad design, unless the margins provided by the oem takes care of the service induced damages. To get better control on the thick walled pipes it is important to introduce the. Sperko engineering buttered and heat treated end can then be welded to the stainless steel using nickel alloy filler metal. Welding processes used in the fabrication of p91 steel are.
In case of greater wall thickness or complex components the possibility of residual stresses must be considered. Sperko engineering accepts no responsibility for proper application of this information or for any consequential damages associated with application of this information. The p91 material is one of the popular choices for welding process that has been used for the last two decades for different applications which is alos made by amardeep steel centre. Basic crmonivwnb alloyed electrode suited for welding of high temperature steel 9%cr1. Tig welding walking the cup pipe welding 2 12inch sch80 carbon steel pipe duration. The electrode features a stable arc, good striking and restriking properties, low spatter loss and an. As compared to smaw,fcaw and saw, gtaw produces one of the cleanest p 91 weld, with very low o2, mn.
For welding,a wide, flat bead is considered best suited. The weld joint was a full penetration butt weld performed on a ugroove on 85 mm. For example, if one of the metals being joined is welded using preheat when welding to itself, preheat should be used in making a dmw. A detailed experimental study was undertaken to examine the suitability of pulsed current gas metal arc welding of 12 mm thick p91 steels in groove joint configurations with metal cored filler wire. Sawp9101 consumables base material welding process root. Welding grade 91 alloy steel this information is provided by sperko engineering based on information currently possessed by sperko engineering. Jun 09, 2016 the heat of the welding process makes the weld deposit and neighboring haz brittle when welding p91. This material has unique characteristics so it can be widely preferred for the construction process and this contributes to the great thermal fatigue life at any point of the time. Filler metal for root weld by gtaw in p91 welding, bonding. For welding creep and hydrogen resistant 9% cr1% mo steels maximum service temperature 650c developed for power plants and the petrochemical industry only available in vacuum sealed sahara readypacksrp sl 9crp91. The heat of the welding process makes the weld deposit and neighboring haz brittle when welding p91. Because precision and stability in temperature control are extremely important when welding p91 pipe, induction heating is a solution that offers better control and. Welding consumables a variety of welding consumables with aws or other national specifications are available for p91 materials. In dissimilarmetal welding, the properties of three metals must be considered.
Boron is added to creep resistant 9crmo ferritic st critical heat affected zones of welded superheater t however similar data on boron containing p91 steel and stress rupture data on this steel at several stresse creep resistance marginally higher. Investigation of weld repair without postweld heat. After welding the joint should cool down below 80c, to finish the martensite transformation. Table 4 provides examples of welding consumables, and table 5 lists consumables for welding p91. No definite standpoint on how long a weld can be left in the as welded condition. Sperko engineering accepts no responsibility for proper application of this information or for any consequential damages associated with application of. Csef, p91, welding, wps, wpqr, wqtr, ndt, preheat, pwht. Dissimilar welds between grade91 to other lower alloyed steels e. Welding is the key factor which can be used during the construction. Postweld heat treatment restores toughness to the weld deposit and the haz. Aug 25, 2011 tig welding walking the cup pipe welding 2 12inch sch80 carbon steel pipe duration. High creep rupture strength and good toughness properties under long term stresses. Pdf the encyclopedia of steel welding p91 combinepdf.
The welding process and electrodes must be suitable for all positions permitted by the wps asme section ix, qw203. En 1011 recommendation for arc welding of ferritic steels. There are tons of examples of p 91 welding with matching filler, which includes, gtaw with p 91 filler. En 719 welding coordination task and responsibilities. We use the p91 matching filler, which is er90sb9 or e9018b9 for welding p91 to p22. En 729 quality requirements for welding fusion welding of metallic materials. Influence of heat treatment in residual stresses generated. Stress corrosion cracking risk of 9%cr martensitic steels between welding and pwht s huysmans, laborelec electrabel gdf suez, belgium main points. Astm a335 p9 tube pwht with tig sg crmovnb 91 welding rodseatment. Normally, preheating, interpass temperatures, as well as the postweld heat treatments are really critical for p91 grade material. Single pass and multipass beadingroove welding were performed on 12 mm thick p91 steel plates using gmawp with metal cored wire at different groove angles as shown in fig.
T91 p91 steel manufactured to astm a335 p91 or astm a2 t91 is a typical tempered martensite in term of microstructure. Jul 07, 2002 at the moment we are welding 6 tubes, 7. Welding process and toughness welding process and the consumables used can dramatically influence the toughness. Properties and welding procedure for grade 91 alloy steel 769 conditions, the welding was done.
Metalspiping not only provides premiumquality t91 p91 seamless pipes and tubes but also supplies optimum filler metals. May 04, 20 hillbilly welder gary from the states and andy from new brunswick tag team a 1. Astm a335 p9 tube pwht with tig sg crmovnb 91 welding. Investigation of weld repair without postweld heat treatment. Meet the demanding requirements of welding p91 pipe with. Harvey shacklock gold medal award crown publications. Pulsed current gas metal arc welding of p91 steels using.
Both the single and multipass welds showed satisfactory bead morphology, tensile strength and toughness especially at higher groove angles of 60. Saw p91 01 consumables base material welding process root. P91 steel, optimization of chemical processes himmelblau pdf containing varying amounts of mnni, and have examined the. The electrode is suitable in all positions except vertical down. Thus, a slight weave technique with high travel speed is specified. Norsok standard 3 of en 473 qualification and certification of personnel for non destructive examination. Unless specifically required otherwise by the welding variables qw250, a qualification in any position qualifies the procedure for all positions.
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