Thermal bulging process for special-shaped bearing steel rolled ring workpieces

Abstract

The invention discloses a thermal bulging process for special-shaped bearing steel rolled ring workpieces, which includes steps of primary bulging; primary rotation; secondary rotation; secondary bulging and tertiary bulging. In the primary bulging, a special-shaped bearing steel rolled ring workpiece which is treated by thermal rolling is sleeved on the periphery of a preheated bulging block in a bulging machine, and the bulging block squeezes the rolled ring workpiece axially along the inner circumference of the ring workpiece after the bulging machine is started so that the primary bulging is completed, wherein the bulging temperature ranges from 880 DEG C to 910 DEG C, the bulging time ranges from 20s to 30s, the pressure holding time ranges from 11s to 16s, and the deflection ranges from 0.4% to 0.8%. The primary rotation is completed by rotating the rolled ring workpiece along the center axis by 45 degrees. The secondary bulging is completed by processes of the primary bulging, wherein the bulging temperature ranges from 850 DEG C to 890 DEG C, the bulging time ranges from 25s to 35s, the pressure holding time ranges from 18s to 20s, and the deflection ranges from 0.8% to 1%. The second rotation is completed by rotating the rolled ring workpiece again along the direction the same with that of the primary rotation. The tertiary bulging is completed by the processes of the primary bulging again, wherein the bulging temperature ranges from 820 DEG C to 860 DEG C, the bulging time ranges from 25s to 35s, the pressure holding time ranges from 18s to 22s, and the deflection ranges from 0.8% to 1.2%. The dimensional precision of the rolled ring workpiece can be 1%. to 2%. of the corresponding precision after the rolled ring workpiece is bulged, and the rolled ring workpiece is mainly used for the fields of space navigation and the like.

Description

technical field [0001] The invention relates to a bulging method for a ring, in particular to a thermal bulging method for a special-shaped ring rolling piece of bearing steel. Background technique [0002] Bearing steel special-shaped ring-rolled pieces (referring to ring-rolled pieces with non-rectangular longitudinal sections) are rolled by ring rolling mills. Due to the influence of rolling process and equipment limitations, their dimensional accuracy is generally not high; only in special-shaped ring-rolled pieces When the shape is ideal and the performance of the equipment is excellent, the dimensional accuracy can reach 3‰~5‰ (three thousandths to five thousandths) of the corresponding size. , If the control is not good in the subsequent processing steps, defects such as warping, deformation and even cracking may easily occur. [0003] The Chinese invention patent specification CN101367104A published on February 18, 2009 discloses a hydraulic bulging strengthening pr...

AI Technical Summary

Problems solved by technology

This method does not disclose in detail how to improve the dimensional accuracy of the ring through bulging, but it is generally concluded that the purpose of improving the forming accuracy of the retaining ring can be achieved, that is, this method cannot solve the size of the special-shaped ring rolling that exists in the prior art The problem of low precision

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