After graduation, the work tendency should be materials, metals can be heat treated, or aerospace materials can be studied. . . . . I am engaged in the mechanical industry. Although I come from a material background, most of my classmates work in the front line. I can't explain your job orientation too much, I can only give you so much advice.
You can get around 4000 in Zhengzhou, but you can't get it just after graduation, and you will die at 3000.