The technical requirements of a large ZTIC Gear ring:
1) is pretreated before normalizing surface hardening treatment, the hardness should HB210 ~ 250; mechanical performance are the ultimate strength Rb 690MPa, yield stress Rs 490MPa, elongation D5 11%, reduction of area W 25% , impact toughness Ak 30J; teeth induction hardened, hardness HRC50 ~ 55; effective hardened layer depth 3 ~ 5mm.
2) overall ultrasonic flaw detection, internal quality should meet two requirements GB7233-87 standard requirements; tooth and fillet magnetic particle inspection, quality should meet two requirements GB/T9444-88 standards.
3) Note the casting is not rounded R5 ~ R10.
4) Tooth chamfer at both ends and 1 45b.5) by two and a half ring gear tooth width of each ring coupling along the edge of a whole ring made with high strength bolts, combined with the tooth surface must be at the bottom center.
2 large ring gear manufacturing process
2.1 of rough
Steel casting blank is provided by CITIC Heavy Machinery Co., Ltd. Heavy Forging plant, run by GB11352-89 standard specifies requirements for modeling according to the casting process, smelting, casting, hit boxes, cleaning, dressing castings;. During inspection and acceptance by the drawings and Technical requirements for steel blank
Checks, according JB/T6402-92 standards issued after acceptance
Down procedure.
2.2 roughing
Crossed by drawing and stay out allowance, alignment, connection, processing both inside and outside the circle, combining face milling, drilling and other processes.
2.3 Exploration injury
Overall ultrasonic flaw detection, internal quality should meet the two requirements of GB7233-87 standards.
2.4 normalizing pretreatment
Semi-ring pairs normalizing and tempering treatment, provide a good organization for subsequent surface hardening; press drawings deformation of the half ring gear inspection after heat treatment.
2.5 Machining
First two and a half ring is made with high strength bolts connecting the ring as a whole, the overall process by drawing a circle Quannei Wai teeth and upper and lower end, and then drawing and machining milling process requirements.
2.6 Elimination of processing stress
The overall ring annealed to eliminate stress.
2.7 overall ring surface hardening
IF along the alveolar tooth surface induction hardening, hardness HRC50 ~ 55, effective hardened layer depth 3 ~ 5mm.
2.8 Final inspection
First, the detection frequency quenching, the hardness after tempering ring gear cogging meets the requirements of the drawings; secondly, to detect whether the maximum outer diameter larger size D6944 as the deformation 3mm, the mechanical correction required until qualified; Thirdly, tooth and fillet magnetic particle inspection, quality should meet two requirements GB/T9444-88 standard requirements; Finally, according to the drawings and technical requirements for final inspection.