Mae gwialen gwresogi trydan dur di-staen (tiwb gwresogi trydan) yn diwb metel fel y gragen, ac mae gwifrau aloi gwresogi trydan troellog (nicel-cromiwm, aloi haearn-cromiwm) yn cael eu dosbarthu'n unffurf ar hyd echel ganolog y tiwb. The gaps are filled and compacted with magnesium oxide powder with good insulation and thermal conductivity. Both ends are sealed with silica gel or ceramics. Gellir defnyddio'r elfen wresogi trydan arfog metel hon yn eang ar gyfer gwresogi dŵr, olew, aer, hydoddiant nitrad, hydoddiant asid, hydoddiant alcali a metelau pwynt toddi isel (alwminiwm, sinc, tun, aloi babbitt), Mae ganddo fanteision effeithlonrwydd gwresogi da , uniform temperature, high temperature resistance, corrosion resistance, and good safety performance.