A METHOD FOR MAKING A BALL VALVE FOR REGULATING A FLUID, A BALL VALVE AND A WELDING TOOL FOR HOLDING AND HANDLING VALVE PARTS

A method for producing a valve (1) for regulating a fluid is disclosed. The valve comprises a valve housing (2) with a central part (3) and with connection ends (4). A ball (5) inside the central part (3) is arranged relative to one or more valve seats (7). The method of producing the valve housing (2) at least includes arranging the at least a first and a second housing parts (2a, 2b) in rotary manner and with the central part (3a) ends towards each other and arranging the ball (5) in a fixed position inside the inner space (3b) of the central part (3). Then, welding the first and a second housing parts (2a, 2b) from outer side of the central part (3) is done while rotating the first and a second housing parts (2a, 2b) and while holding the ball (5) in a fixed, non-rotating position inside the central part (3). During the welding step, a protective gas is supplied to the inner space (3b) of the central part (3). The result is a valve housing with a single welding seam arranged at the central part (3) of the valve housing (2). A valve and a welding tool for holding the valve parts during the welding step is also disclosed.