Relevance Between The Weld Grain Size And Welding Process Parameters Of P-TIG Of Inconel601H Nickel-based Alloy

Inconel601H nickel-based alloy is a kind of solid solution strengthening type nickel-based alloy with good high temperature mechanical properties and corrosion resistance, soit was widely used in the field of petrochemical, aerospace and thermal power. In order tocontrol the weld coarse grains of the nickel base alloy, and study the effects of processparameters on weld grain size, this paper uses Inconel601H nickel-based alloy as test objectusing the P-TIG welding, the P-TIG welding process parameters on weld grain size andoptimum technological parameters combination was discussed, and the process parametersinclud peak current, base value current, pulse frequency, pulse ratio and cooling rate.Withthe optical microscope, the microstructure of the weld junction was observed and the grainsize was calculated after welding.The main conclusions were shown as following:(1) The effects of welding processparameters on the size of the weld grain were different under the P-TIG of the Inconel601Hnickel-based alloy. With the peak current, pulse frequency and pulse on time increased in acertain range, the effects of the grain refinement are obvious; however, the grain tends togrow up with the increase of the base current of welding. And with the increase of coolingrate, grain size change is not obvious.(2) Using proper technological parameters can help toimprove the problem of weld coarse grains, the weld area performance can be greatlyimproved, and welded joint strength can be improved to a certain extent, and the weldingquality can be improve under the P-TIG of the Inconel601H nickel-based alloy.(3) Taguchimethod is a kind of very scientific testing methods to design and optimize the weldingprocess parameters.By taguchi method the results were analyzed, the optimal weldingtechnological parameters combination were found out.The peak current is250A, the basevalue current of20A, the frequency is10Hz, the duty ratio is70%.(4) The verification teston the best welding technological parameters combination were carried out, and the weldsmallest grain were acquired.