Shafting. All shafts are made from steel conforming to BS 970 Part 1, Grade 080M40 or its equivalent relevant international standard. Shafts are manufactured to standard commercial tolerances for diameter and straightness. No surface heat treatment is allowed. Shaft journals and fillet radii are machine finished to a maximum of 63 rms. Coupling mounting surfaces are concentric with the nearest bearing journal within 0.0003 times the bearing journal diameter or 0.025 mm, whichever is the greater. Where couplings, or the equivalent, are to be mounted the surface roughness is to be within RA 2.5 µm. Note: ISO tolerance h7 applies to coupling seating. 25 50 11 50 80 13 80 120 15 120 180 18 180 250 20 250 315 23 315 400 25 400 500 27 500 630 29 630 800 32 800 1000 35 The shaft contact pressure under the locking device is calculated for the inside and outside shoulders. The alternating stress range, at the shoulders, shall not exceed the shaft material’s endurance limits as defined by the Modified Xxxxxxx Diagram. The minimum contact pressure shall exceed 100 MPa for all operating conditions. All shafting is ultrasonically inspected. The allowable maximum shaft stresses for material is as follows: Bending only - 56 MPa Combined stress:
i. Shear at hub, not key seated - 40 MPa ii. Shear at turndowns - 40 MPa Shear stresses are calculated according to CEMA’s “Belt Conveyors for Bulk Materials”, second edition, with Kb = 1.5 and Kt = 1.0. At turndowns, stress concentration factors are applied for bending and torsion as per “Stress Concentration Factors” by R.E. Xxxxxxxx.
Shafting. Dye penetrant inspection is provided for all turndown sections after machining. Shafts are ultrasonically tested to note any internal cracking. The procedure is in accordance with ASTM A-609-81 and A-609-81 S1, with the acceptance Level ll or DIN equivalent. All forgings are ultrasonically inspected before machining. Steel castings shall also undergo magnetic particle inspection over their entire surface in accordance with ASTM E-709-80 and ASTM E-125-80 or DIN equivalent. Acceptance criteria for magnetic particle inspection is zero linear discontinuities. The surface of steel castings are machined free of pitting and surface cracks, with surface defects not exceeding 0.75 mm in depth and 25 mm in diameter. Shaft deflection on pulleys is limited to 6 minutes and a taper locking device must be used.
Shafting a. All shafts are made from steel conforming to BS 970 Part 1, Grade 080M40 or its equivalent relevant international standard.
b. Shafts are manufactured to standard commercial tolerances for diameter and straightness.
c. No surface heat treatment is allowed.
d. Shaft journals and fillet radii are machine finished to a maximum of 63 rms.
e. Coupling mounting surfaces are concentric with the nearest bearing journal within 0.0003 times the bearing journal diameter or 0.025 mm, whichever is the greater. Where couplings, or the equivalent, are to be mounted the surface roughness is to be within RA 2.5 µm. Note: ISO tolerance h7 applies to coupling seating. CONTRACT 44 ECC3 COVER PAGES 25 50 11 50 80 13 80 120 15 120 180 18 180 250 20 250 315 23 315 400 25 400 500 27 500 630 29 630 800 32 000 0000 00
f. The shaft contact pressure under the locking device is calculated for the inside and outside shoulders. The alternating stress range, at the shoulders, shall not exceed the shaft material’s endurance limits as defined by the Modified Xxxxxxx Diagram. The minimum contact pressure shall exceed 100 MPa for all operating conditions.
g. All shafting is ultrasonically inspected.
h. The allowable maximum shaft stresses for material is as follows: Bending only - 56 MPa Combined stress:
i. Shear at hub, not key seated - 40 MPa ii. Shear at turndowns - 40 MPa
i. Shear stresses are calculated according to CEMA’s “Belt Conveyors for Bulk Materials”, second edition, with Kb = 1.5 and Kt = 1.0. At turndowns, stress concentration factors are applied for bending and torsion as per “Stress Concentration Factors” by R.E. Xxxxxxxx.
Shafting x. Xxx penetrant inspection is provided for all turndown sections after machining.
b. Shafts are ultrasonically tested to note any internal cracking. The procedure is in accordance with ASTM A-609-81 and A-609-81 S1, with the acceptance Level ll or DIN equivalent.
c. All forgings are ultrasonically inspected before machining. Steel castings shall also undergo magnetic particle inspection over their entire surface in accordance with ASTM E-709-80 and ASTM E-125-80 or DIN equivalent. Acceptance criteria for magnetic particle inspection is zero linear discontinuities. The surface of steel castings are machined free of pitting and surface cracks, with surface defects not exceeding 0.75 mm in depth and 25 mm in diameter.
d. Shaft deflection on pulleys is limited to 6 minutes and a taper locking device must be used.
