The invention provides a manufacturing method of an X70QS seamless line
pipe for an acid environment, comprising the following steps: 1.
steelmaking, i.e. electrosmelting, external refining, carrying out VD or RH vacuum treatment, carrying out
silicon-
calcium wire treatment, and adopting a continuous-
casting short-flow process combined with a clean steel
smelting technology for controlling the content of P, S and inclusions; 2. tube rolling, i.e. adopting a hot-rolling seamless
pipe process at the
continuous rolling temperature of more than 950 DEG C, jointly controlling the
dimensional precision of the tube by a PQF three-roll mill and a tension-reducing mill or a
sizing mill; and 3. heat treatment, i.e. under the
quenching temperature of 910-980 DEG C and the
tempering temperature of 550-730 DEG C, carrying out high-temperature
sizing and straightening control at the temperature of 480-630 DEG C to guarantee performance and size of the
pipe. The manufacturing method has the advantages of accurate composition design,
high dimensional control accuracy, low manufacturing cost and easy production; and the pipe obtained by the method has good
mechanical property and good
corrosion resistance, thus being applicable to a high-pressure gas delivery pipeline under an acid condition.