Metallurgy Big Mill Girth Gear Ring Tooth Of Mining Equipment Parts

Big Mill Girth Gear Ring Tooth Ring Of Mining Equipment Parts

1. Manufacturing process of big tooth ring for mill girth gear

(1) Blank

The steel casting blank is provided by the heavy casting and forging Plant of CITIC Heavy Industry Machinery Co., LTD. It is implemented in accordance with gb11352-89 standard. Molding, smelting, pouring, box beating, cleaning and dressing castings according to casting process requirements; During the inspection and acceptance, the cast steel blank shall be checked according to the drawings and technical requirements, and the process shall be put down after passing the acceptance according to JB/T6402-92 standard.

(2) Rough machining

Draw lines according to the requirements of the drawings and set aside processing allowance, alignment, connection, processing inner and outer circle, milling joint surface, drilling and other processes.

(3) Agent injury

Ultrasonic inspection shall be carried out on the whole, and the internal quality shall meet the secondary requirements of GB7233-87 standard.

(4) Normalizing pretreatment

The half ring is normalized and tempered in pairs to provide good microstructure for subsequent surface quenching. And according to the requirements of the drawings to check the deformation of half gear ring after heat treatment.

(5) Machining

The first two half ring with high strength bolt connection into a whole ring, according to the requirements of the drawings processing of the whole ring circle and upper and lower end, and then according to the drawings and machining requirements for milling teeth.

(6) Eliminate machining stress

The integral ring is annealed to eliminate stress.

(7) Surface quenching of integral gear ring

Tooth surface medium frequency induction quenching along the tooth groove, hardness HRC50~55, effective hardening layer depth 3~5mm.

(8) Final inspection

Firstly, test whether the hardness of each groove of the gear ring after intermediate frequency quenching and tempering meets the requirements of the drawing; Secondly, detect whether the size of the maximum outer diameter D6944 is too large, such as the deformation of 3mm, need mechanical correction until qualified; Thirdly, for magnetic particle inspection of gear teeth and transition fillet, the quality should meet the secondary requirements stipulated in GB/T9444-88 standard; Finally, according to the drawings and technical requirements for the final inspection.

2. Product parameters of big ring for mill girth gear

3. Technical requirements of large gear ring for mill girth gear

(1) The surface pretreatment before quenching is normalized, and the hardness should be HB210~250; Mechanical properties are strength limit Rb690MPa, yield limit Rs490MPa, elongation d511%, area reduction w25%, impact toughness value Ak30J. Tooth induction hardening, hardness of HRC50~55; Effective hardening depth 3~5mm.

(2) Ultrasonic inspection shall be carried out on the whole, and the internal quality shall meet the secondary requirements stipulated in GB7233-87 standard; Gear tooth and transition fillet magnetic particle inspection, quality should meet GB/T9444-88 standard requirements.

(3) Uncast rounded corners R5~R10.

(4) Chamfering of both ends and edges along the tooth width. Big gear ring by two half gear ring connected with high strength bolts into a whole gear ring, the joint surface must be in the center of the tooth bottom.

Mill Girth Gear