Extended Reducing Nipple

Product Name: Extended Reducing Nipple

Product Specification: DN6-DN300

End Face Type: Large end beveled / Small end plain, Large end beveled / Small end taper pipe thread, Large end plain / Small end taper pipe thread, Both ends beveled, Both ends plain, Both ends taper pipe thread

Material: 20#, A105, 16Mn, 304, 304L, 316, 316L, 1Cr5Mo, 12CrMo, 12Cr1MoV, 15CrMo

Manufacturing Standards: SH/T 3419-2007, MSS SP 95

Product Features: Reducing nipples are formed by die forging and cutting processing, with specifications indicated by nominal diameter DN. Reducing nipples include straight nipples and eccentric nipples. During the die forging of nipples, the stress state varies greatly at different parts of the blank, and the stress state of the same point also differs in different deformation stages. Therefore, each point has an independent force trajectory in the principal stress space. For cylindrical reducing nipple blanks, the average stress on the outer circular surface is relatively high, and radial stress occurs at the initial stage of deformation, which is a key cause of longitudinal cracks easily appearing on nipple blanks. To measure the flow stress at room temperature, nipple blanks can be rolled in advance with different deformation degrees to enable blank specimens to achieve work hardening corresponding to their deformation, followed by the measurement of yield points under tension and compression. The deformation temperature of nipples is a critical factor strongly affecting flow stress. In general, flow stress decreases as the deformation temperature rises for the following reasons: 1. With the increase of deformation temperature, the amplitude of atomic thermal vibration of reducing nipples increases, creating conditions for the simultaneous operation of effective plastic deformation mechanisms, reducing slip resistance and generating new slips continuously. Meanwhile, the amorphous diffusion mechanism and intergranular viscous flow of reducing nipples are enhanced, resulting in lower flow stress. 2. Dynamic recovery and dynamic recrystallization occur at high temperatures, which soften the deformed metal to a certain extent and even completely eliminate the work hardening effect of nipples, thereby reducing flow stress.