What should I do if the steam keeps coming out from the place where the liquefied gas tank is unscrewed?

Can’t you close it? If it's a turnbuckle, there's basically no cure for the outgassing. If it's a small one, you can still fix it and apply some glue. If it's a big one, there's nothing you can do about it. Place it outdoors, away from fireworks, and put eye-catching slogans to warn others about the danger. Get close,

If the top valve cannot be closed, use an 8-10 wrench to unscrew the screw, remove the valve, and use the wrench to tighten it horizontally, try it and see if it works,

Finally, I called the gas supply company directly and asked for a replacement. . . .