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The most common method of cutting welded steel tube mill has been friction
saw and next by COC cutters. But these methods are not fast enough and can
be used only upto Mill Speed of 75 mts/min. This limits the speed of the
tube Mill & hence the capacity.
Next came the faster method of cutting tubes on Tube Mill. Ie Punch type
tube Cut off. This can accommodate tube speed upto 200 mts./mts. The cutting
principle employed is shear force applied by a mechanical / Hydraulic/
Pneumatic device.
Other advantages of using Tube Cut-Off system are –
(a) High length accuracy ie _/1 1 mm on 3mts. Length at Mill Speed of
150 mts./min.
(b) Suitable for round and section tubes.
(c) Cutting is burr free.
Tube Cut off knife plays an important role in Punch Type Tube Cut-Off system
Dee Tee Tube Cut-Off Knife is made from High Speed Steel (AISI-M2) and moves
up and down at high speed. While cutting tube, it passes through a set of
dies and clearance between knife and dies is very fine which asks for a
closer thickness tolerance on knife. Apart from thickness, warpage should be
well controlled to avoid breakage while moving through dies.
FEEDING LENGTH SIGNAL CLAMPING SCARF REMOVAL TUBE
CUTTING
Punch type tube cut-off system( Burr Free, Double blade Type)
(A) Recommended Tolerance On Dee Tee Tube Cut Off
Knives :
1 Hardness:-
61 HRC- base hardness, within +/-1 HRC ( if not apecified in drawing)
2 Thickness Tolerance
- 0.025/-0.00 mm length of knife 0 to 150 mm.
- 0.035/-0.00 mm, length of knife above 150 upto 300 mm.
- 0.045/-0.00 mm, length of knife above 300 mm.
3 Warpage
0.02 mm per 100 mm length.
0.015 mm within 75 mm depth from hole side
4 Perpendicular, side to bottom
within 0.025 mm per 100 mm.
5 Center distance of holes
within +/-0.25 mm.
6 Width Tolerance
within -0.05/+0.00 mm
7 Surface Finish
0.2 Ra or Better.
(B) PARAMETER OF PRIME IMPORTANCE FOR TUBE CUT-OFF
KNIVES.
1. Hardness.
2. Wear Resistance
3. Toughness
4. Edge Retention
5. Impact resistance.
AISI M2 is the best raw material for tub ecut off knives considering above
requirements. Knives are also available TIN COATED. These TIN COATED knives
give beter life. On Bond Tin Coating, 2/3 microns give good hardness low
coefficient of friction corrosion resistence which increases tool life 2 to
3 times.
(C) CHEMICAL COMPOSITION OF RAW MATERIAL
AISI-M2 : C Mn Cr MO V W
0.86/0.94 0.15/0.40 4.0/4.5 4.7/5.2 1.7/1.9 6.2/6.6
Tools which last longer – Slitting Line Tooling, Tube / Section Mill Rolls,
Tube Cut Off Knives, Cold Rolling Mill Rolls, Leveller Rolls, Fins , Steel
Centers, Chipper Knives, Friction Saws, Shear Blades, HSS Saw & C.T Saw
Bodies.
OTHER ARTICLES
NON
DESTRUCTIVE TESTING OF COLD ROLLING MILL ROLLS
SUB ZERO
TREATMENT (Reduction in Retained Austenite)
TUBE CUT OFF KNIVES
TIGHTER
MANUFACTURING TOLERANCE FOR ROTARY
CUTTER,
SLITTING KNIFE AND SPACER.
CRYOGENIC
TREATMENT
HINTS & TIPS ON THE APPLICATION OF
SLITTER TOOLING
GUIDELINES
FOR RAW MATERIAL SELECTION FOR SLITTING LINE TOOLING
SHEAR BLADES AND MACHINE KNIVES
PRECAUTION & ORDERING
TIPS FOR FRICTION SAWS
FINS AN IMPORTANT
COMPONENT OF TUBE MAKING
IMPORTANT FACTORS
IN COLD ROLLING MILL ROLLS
DEE TEE FORGES YET AHEAD IN SEARCH OF
EXCELLENCE
SLITTER TOOLING OVER ARM
SEPARATORS |
