????? ?????? ??? by by 4130 Seamless Tubing in Contributions of Contributions of Contributions. Introduction to 4130 Seamless Tubing 2 Unis ???????? 4130 Seamless Tubing 2.1 ???????? ??????? ?????? ???? ??? 3.1 ?????? ??? Durability 3.2 Corrosion Resistance 3.3 Lightweight and multiplatile 4