Inconel 718 Trials — Хонинговальные головки

Three grinding wheels listed in Table 19.5 were each tested using an L827 orthogonal array to determine the most favorable conditions.

The aluminum oxide wheel listed having 42% porosity gave better results than a number of other aluminum oxide wheels tested for grinding Inconel 718. The CBN wheels listed also had increased porosity, 40% compared with 35% and showed improved grinding performance for Inconel 718. Porosity was selected based on work by Cai [2002].

0.7

0.1

AB CDE FGH Parameter

Dressing:	A1 = down	A2 = up
Dressing overlap:	B1 = 2	B2 = 10
Dressing depth:	C1 = 2 pm	C2 = 10 pm
Dressing passes:	D1 = 2	D2 = 10
Wheel speed:	E1 = 60 m/s,	E2 = 120 m/s
Workspeed:	F1 = 36 m/min	F2 = 54 m/min
Finish feed:	G1 = 5 pm at 1 ^m/s,
Dwell:		G2 = 10 s
Dresser speed:	H1 = 42 m/s	H2 = 72 m/s

TABLE 19.5

Grinding Wheel and Machine Combinations for Grinding Inconel 718

Abrasive Type	Wheel Details	Wheel Speed (m/s)
Vitrified Al2O3	A80 J6V	45
Vitrified CBN	B151 (Medium speed)	45
Vitrified CBN	B151 (High speed)	60-120

Best dressing and grinding conditions for the three wheels used for Inconel 718 were

• Conventional-speed Al2O3 wheel. The wheel was dressed with a single-point diamond, ad = 2 pm, vd = 1.2 mm/s, and nd = 2. Grinding conditions were vs = 45 m/s, vw = 20 m/min, tso = 10 s, and Q’w = 2 mm3/mm/s.

• Conventional-speed vitrified B151 CBN wheel. The wheel was dressed at vr = -12.6 m/s, ad = 2 pm, vd = 1.4 mm/s, and nd = 2. Grinding conditions were vs = 45 m/s, vw = 20 m/min, tso = 10 s, and Q’w = 2 mm3/mm/s.

• High-speed B151 CBN wheel. The wheel was dressed at vr = -42 m/s, ad = 2 pm, vd = 8.5 mm/s, and nd = 2. Grinding conditions were vs = 120 m/s, vw = 26 m/min, tso = 2 s, and Q’w = 2 mm3/mm/s.