Plasma Cutting of 75mm and 88mm thick Stainless Steel Plates

Plasma Cutting of 75mm and 88mm thick Stainless Steel Plates

LIVE VIDEO of Heavy SS Plate Cutting

ICEM Ltd based in Thane is a leading manufacturer of Dished ends established since the last 30 years and today supplies dished ends to the largest fabricators in India and abroad. In February 2003 ICEM received an export order for 4 dished end to be fabricated out of 72 mm, 75mm, 82mm and 88 mm thick stainless steel plates. The min dia was 4570mm and 5340mm weighing 15 tons and 25 tons respectively. The thickness and size of the plates was so high so as to completely rule out forming the dished end from a single plate. The chosen mode of fabrication was therefore to cut the petals and the round plate from individual plates form it to the desired shape (radius) in the power presses and then weld it together.

quipments (I) Pvt Ltd they had only 2 weeks to manufacture and install the system.

CUT PLATES The delivery time was critical with penalties for late delivery and when the order was placed for a plasma cutting system with Arcraft Plasma E

Arcraft Plasma Equipments (I) Pvt Ltd beating all expectations not only manufactured and supplied the system but also gave the job cutting finish and life of consumables, which was highly appreciated by ICEM Ltd. 

The average life of the electrode was 6 hrs and nozzle was more than 12 hrs of continuous cutting 88 mm thick plates. In fact the addition of a chilled water recirculator increased average consumable life by 300 percent.
The cut finish at 75mm and even 88 mm was absolutely dross free with no need for post cut operations except a little bit of grinding.

CUTTING IN PROGRESS 88 mm THICK PLATE.

The system consists of a power source, water-cooled torch, water recirculating cum chilling unit and control console.

Here is what ICEM Managing Director V V Tibrewala had to say about the machine supplied by ARCRAFT. It was a challenge for us to undertake dished end fabrication of SS plates of this thickness and dia. Even today there are very few fabricators in India who would work at this thickness of Stainless steel. The most essential job was to have a reliable plasma cutting system to cut the plates after which we could proceed with the balance work. We are happy to say that Arcraft Plasma Equipments (I) Pvt Ltd not only supplied the machine in time but also gave a wonderful machine whose performance exceeded even our expectations. It is truly a world-class machine. 

Given below are the cutting cost estimates for cutting 88mm Stainless Steel plates. The calculations include cost of power, consumables and gas. The cost of labour and handling has not been included as it may vary.

Report on Plasma Cutting - For 88mm thickness SS Plate.

Machine Specification
Machine Model: ARC CUT 100-3S (Arcraft Plasma Equipments (I) Pvt Ltd )
Input Voltage: 415 VAC + / - 10%
Installed Power: 90 KVA
Open Circuit Voltage: 350 VDC
Load Voltage: 180 VDC
Max Output current: 300 Amps
Current Control: 3 Steps 
Soft start mechanisms: Yes

Gas/Coolant Used
Torch Coolant: Water
Machine Coolant: Forced Air
Plasma Gas: Nitrogen 
Consumption Rate of Plasma Gas: 2.8m³ per meter (of cutting length)

Material Specification
Material: Stainless Steel
Plate Thickness: 88mm
Kerf Width: < 8mm
Cutting Speed: 28 mm/min
Increasing output current can increase cutting speed

Consumables' Detail
Life of Electrode: 10 meters (of cutting length)
Life of Nozzle: 20 meters (of cutting length)

Based on actual results at ICEM LTD with standard water-cooling system.
With Chilled water recirculator life can increase up to 300 %

Estimated cost of Operating/Running Plasma Machine (ARC CUT 100-3S)

Input Current (A): 125 Amps
Input Voltage (V): 415 Volts
Power Factor (PF): 0.7
Length of cut in 1 hr (LC): 1.680 meters
Life of Electrode (LE): 10 meters (of cutting length)
Life of Nozzle (LN): 20 meters (of cutting length)
Cost of Electrode/Nozzle (C): Rs. 150/- each
Cost of Nitrogen Gas (CG): Rs. 300/- (for a 7m³ cylinder)
Consumption Rate of Plasma Gas (CR): 1 cylinder per 2.5 meters (of plate cutting length)

Power Consumption (KVA) = /3 x V x A
= /3 x 415 x 125
= 90 KVA

Power (KWhr) = PF x KVA
= 0.7 x 90
= 63 KWhr

Power Cost @ Rs 6/- = KWhr x 6
=63 x 6
= Rs 378 per hr


Electrode cost for 1 hr = C/LE x LC
= 150/10 x 1.68
= Rs 25/-

Nozzle cost for 1 hr = C/LN x LC
= 150/20 x 1.68
= Rs 12.50/-

Cost of Nitrogen Gas per hr = CG/CR x LC
= 300 / 2.5 x 1.68 
= 202

Total Cost = 378 + 25 + 12.50 + 202
= Rs 617.50/- (for 1.68 meters)

Total Cost/meter = Rs. 368/-
(For 88mm thick SS plate)


Rs 48 equals 1 US Dollar approximately.

Above Test results are based on actual trials at ICEM LTD, Thane, Maharashtra.

1. Standard water recirculator consisting of condenser with forced air-cooling was used.
2. Test with chilled water system showed 300 % increase in life of consumables. 
3. Best results are obtained for continuous cutting without frequent start - stop cycle. 
4. It is possible to increase cutting speed by increasing output current of the power source.

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