The weldability of BFe10-1-1 and the manufacture difficulties of the floating head cover arch covering-floating head flange joint and the tube-tube sheet joint are expound. The welding process of the joints is also introduced, including the selection of welding material,welding preparation, welding technology and so on. And the matters needing attention in welding process are pointed out,the welding of the actual product are finished, and its nondestructive testing result is qualified according to relevant standards. This proves that the whole process of welding technology is reasonable and good quality products can be obtained according to this welding technology.