Friends, do have any idea about what is cold cutting? A cold-cutting process, as the name implies, it is a method of cutting without the use of heat. This efficient slice or cutting system is used in a variety of industries such as material processing, chemicals, pharmaceuticals, oil painting, petrochemicals, gas and many more.
Let us learn further about the cold cutting process, its description, causes, benefits, and different types of cold cutter or cold cutting machines to clear the basic concept.
What is Cold Cutting? Definition & Meaning
Cold cutting is a procedure that cuts material without the use of heat. Because no sparks are produced, this process is the safest way to cut structures in hazardous environments. As there is no application of heat, this process is named as cold cutting. Typical industries where cold cutting is preferred are the oil, gas, and petrochemical industries.
Three commonly used types of cold-cutting machines are tube cold-cutting machines (also called clamshell cutters), cold-cutting diamond saws, and waterjet planers and we will learn all these in this article.
What is Pipe Cold Cutting?
Cold cutting is widely applied in pipe cutting process and from this the term, ‘pipe cold cutting’ is introduced.
- Modern cold cuts can cut pipe from less than 1 inch to over 120 inches.
- It can cut any of the weld joint flanges commonly used during pipe cutting to complete the final setup.
Don’t be confused with flame cutting and grinding with respect to cold cutting. Flame cutting and grinding can cause very hazardous conditions in the presence of hydrocarbons, whereas cold cutting, as the name suggests, produces no sparks and produces very little heat, making it an inherently safer cutting method.
Cold cutting is a versatile, precise, and safe method of cutting pipe that allows the operator to operate the cutting tool from a safe distance. Additionally, there is no HAZ (heat-affected zone) that can change the properties of the material.
Why Do We Use Cold Cutting?
We all know, Heat and flames are dangerous hazards in the hydrocarbon industry. However, due to lack of heat from the torch, cold-cutting technology eliminates the majority of serious accidents caused by the heat and flame in hydrocarbon industry. As a result, cold cutting has advantages in a variety of tasks, including pipeline repair, maintenance, shutdown activities, and start-up.
By using the cold-cutting method, the risks associated with hot cutting are eliminated. This is the main reason for the ever-increasing cold cutting of pipes and structural elements. The main reasons why people use pipe cold cutting are described below:
- Safe Work: A cold working environment is safe for tool operators which maintains a safe environment to work with.
- No Heat: As there is no heat, no possibility of an accident due to burning or explosion.
- Time: It is easy, and this can also be finished in less time.
- Money: Cold cuts are cheaper compared to hot cuts. So, cold cuts fit easily into the small project budget.
What is Cold Cutting Machine or Cold Cutter?
A cold-cutting machine is a tool used in Operations involving cold-cutting. They are really compact, durable, portable, and lightweight, and are also known as “cold cutters.” Cold-cutting machines come in a variety of configurations. In 1949, E. H. Wachs has invented this cold-cutting technology. There are different types of cold cutting machines available in the market. Now, how do we choose which one to be used? It depends on the various factors:
- The application, which material has to cut by this process. Different material may require different process.
- Required location.
- The level of accuracy, perfection, finish required.
- Economic sustainability.
How Does Cold-Cutting Process Work?
Cold cutting process is typically done in the following two main steps:
- Cutting preparation
- Operate cold-cutting machine
Step1: Cutting preparation
The step for cutting preparation are as follows:
- Raise the cutter spindle to the highest position by rotating the feed screw with the blade lifting handle.
- The start/stop control and machine direction control are then turned off. Then, set the machine speed and blade control to fully closed. The manufacturer’s specifications for pneumatic or hydraulic power are followed.
Step-2: Operate cold-cutting machine
- The operation of this machine should be done by a trained operator.
- Cold cutting machine shall be correctly positioned.
- Wheel carriers must be positioned correctly to improve stability and performance.
- Turn on the trimmer
- Ready to the process.
- Rotate the cutter to perform the cold cutting.
Types of Cold-Cutting Machines
Based on Drive Mechanism Cold Cutting Machine Types
Depending on the drive mechanism, cold-cutting machines are divided into two groups:
- Pneumatic cold cutting machines, or air driven cold cutting machines.
- Hydraulic cold-cutting machines.
Based on Application Cold Cutting Machine Types
Depending on the application, cold-cutting machines are as follows:
- Pipe or tube cold cutting machines.
- Clamshell pipe cutter
- Band saw, diamond wire saw,
- Abrasive waterjet cutting
Let’s discuss all types of cold cutting machines which are widely used in various industries:
Description of Widely Cold Cutting Machines
Pipe or Tube Cold Cutting Machine
Whenever we talk about cold cutting machines, there are a few names come in our mind. Tube or pipe cold cutting machine is one of them. With its round structure, the tube-cold cutting machine can easily wrap the tube in half and join with a hinge. A rotary cutting tool runs around the tube. Cold pipe cutting machines cut different pipe diameters and are ideal for precise applications. According to size and capacity, there are three types of tube cold cutting machines:
- Cold cutting machines used for large pipe i.e., large pipe cold cutter
- Cold cutting machines used for medium pipe i.e., medium pipe cold cutter
- Cold cutting machines used for small pipe i.e., small pipe cold cutter
Clamshell pipe cutter
Clamshell pipe cutter Description
A portable cold pipe cutting machine used to cut as well as to chamfer pipe is a clamshell pipe cutter. Lightweight, small in size, and available with a variety of cutters Steel pipe, Hastelloy, SS, SDSS, alloy steel, Inconel, and clad pipe can all be cut with this tool. Split frame technology has the ability to cut thick tubing and provides a variety of unique features such as:
- Faster and more accurate process
- Complete operating system with quality accessories
- Precision cutting
- Tracer tip for even ground
Clamshell tube cold cutting machines are developed for high metal removal rates, a wide adjustment range for huge diameters, and easy on-site set-up. A portable clamshell lathe cutter for pipe cutting and chamfering avoids the heat-affected zone (hazard) in the pipe cutting process.
Designed for heavy-wall tubing in the HD applications. High working speed and quick set-up enable quick operation in the field. DLW-HD clamshell lathe cutters can operate safely and precisely in the mainly critical applications. Steel frame construction combined with high-quality steel gears and bearings provides a durable combination that can withstand the most demanding jobs.
The DLW-HD type, 48 to 57 inches. Clamshell tube cold cutting machines are evolved for the rates of high metal removal, a wide adjustment scale for huge diameters, and easy on-site set-up. A portable clamshell lathe cutter for cutting of pipe and chamfering avoids the zone of heat-affected (hazard) in the process of pipe cutting.
Designed for such heavy-wall tubing in the HD applications. High working speed and swift set-up enable quick operation in the field. DLW-HD of clamshell lathe cutters operate safely and precisely in the mainly critical applications. Steel frame construction combined with high-quality of steel gears and bearings give a durable combination that can withstand the most demanding jobs.
Advantage : portable cold pipe cutting machine. The saw diameter range for cold-cut tubing is from 48″ to 72″ OD. for walls up to 100 mm thick. The frame splitter can be attached to the assembled pipe substrate. Special applications such as remote control are available when access to welding pipes and tubes is restricted.
A super cutting tool for the cold scallop cutter, tool bit solutions for tube cold cutting and chamfering, developed in collaboration with German universities, deliver excellent results in the cold cutting process and high rate of metal removal, have more durability, fewer consumable, low cost tools of cutting,
Heavy pipe cutting with two cutters. Various preparations for cold rinse welding using high-speed section steel. Simultaneous cutting and edging of thick-walled pipes. Chamfer both ends of the tube simultaneously (depending on the wall thickness).Technical features of a cold pipe cutting machine. A motor is an essential component of a pipe cutting machine in terms of reliability and productivity.
All motors are Western European or American standards. Adapters allow easy exchange of all types and sizes of motors (pneumatic and hydraulic). The automatic feed mechanism enables stable work progress. A variety of actuator options are available, including pneumatic, hydraulic, and electric actuators. Let’s see the Advantage and Disadvantage of clamshell pipe cutter
Advantage:
- A cold pipe cutter with endless pipe splitting frame technology.
- Compact dimensions for use in tight workspaces with limited access.
- Fast and safe clamping and adjustment of pipeline welds.
- Cold cutter for solid pipe for pipeline welding.
- High metal removal rate operation.
Disadvantage:
- Heavy pipe cutting with two cutters.
- Various preparations for cold tilt welding using high-speed section steel.
- Simultaneous cutting and edging of thick-walled pipes.
- Chamfer both ends of the tube simultaneously (depending on wall thickness).
Band saw, diamond wire saw
Diamond wire saws are the most flexible cutting method in the field of component and material quality assurance. The thinnest cutting edge is 0.08–0.5 mm. Since it cuts “gently,” there is little heat entering, and it is possible to cut parts such as rubber that are sensitive to temperature. Both wet and dry cutting are possible.
Cutting operations are usually precise, uniform, and smooth. The cut edges are sharp and there is no caulking. When cutting composite materials, there is no bleeding between different materials. There is no problem up to a cutting height of 375 mm. The disadvantage is that the slow feed rate increases the cutting time, but this is less important in the laboratory.
Band saws and diamond wire saws are widely used in the chemical industry where high precision cutting is not a must. It is powered by hydraulic components and needs the appropriate hoses as well as a hydraulic power pack. The cutting surface of a cold band saw cutting machine heats up during operation, so a suitable coolant must be used.
Band saws and diamond wire saws are both used in the gas and oil industry. Both are used to disable projects where accuracy isn’t as critical. This large, tough portable band saw can be used on oil rigs to cut cylindrical structures. However, this is not completely a cold cut because sparks are likely to occur in the absence of coolant. Pipelines, caissons, and piles are all cut with subsea diamond wire saws. In piece of a blad, diamond-wire saws use a beaded rope crusty covered with tiny diamonds on the outside. The rope’s round cross-section surely makes it less liable to compression as well as jamming problems that metal blades sometimes encounter. Similar to a band saw, when it is used upside down (on water), it requires coolant rather than original cold cutting action.
Abrasive waterjet cutting
Cold water jet abrasive cutting is used in areas where there is a risk of fire or explosion. This method employs extremely high water pressure (approximately 4137 bar). In water, crush and cut solid abrasives. This method works well with thick metals, concrete, and composites. Cold jet abrasive cutting is one of many methods of cutting structures on-site without the use of heat. This will make the process suitable for fire and explosion-hazard environments.
How does waterjet cutting work?
Abrasive waterjet cutting is mainly an accelerated wear process. High-pressure of water is ejected from a sapphire or the diamond, and a “mixed chamber” produces a vacuum that draws pomegranate sand into the stream of water. It means that waterjets are obviously powerful and versatile tools of cutting and are used all over the world for a large variety of applications in the waterjet cutting.
The process itself begins with a wide electric oil pump that pumps 2,750 psi or approximately 190 bar of oil through a weighty duty condenser assembly (pressure booster). The pressure in the condenser rises from a local supply pressure of 50 to 60 psi (3.45–4.15 bars) to 55,000 psi or around 3792 bars.
This pressure increase is achieved by increasing the outside area of the hydraulic piston (20 times the outside area of the water piston) to increase the water pressure 20 times over the hydraulic pressure. High-pressure of water is then supplied to the cutting head through pressure tubes. At the head of cutting, a high-pressure stream of water is focused through a sapphire, ruby, or diamond orifice, concentrating the water into a pure “needle.”
High-pressure water is then ejected from the mixing chamber as the abrasive sand of garnet is drawn in the water stream. The abrasive-water mixture is discharged from the head of cutting through a concentrating tube at total speeds up to 2 m/s, creating an extremely efficient and powerful cutting tool. This procedure cuts metal, composite or concrete materials. Examples of field applications include drilling holes in vessels and storage tanks and large-diameter cutting tubing.
When cutting pipe, cutting with an abrasive water jet is less appropriate than a clamshell cutter due to the need to deal with waste water products. Also, there is the huge risk of damaging surrounding materials and coatings. However, this thing can be minimized by installing a plate to prevent unwanted spraying of the polishing liquid.
Abrasive water jet cutting can actually cut extremely thick and wide materials, such as 150-mm-thick concrete plates and 100-mm-thick iron plates. The lack is that the thicker the film, the lower the resolution. The farther the nozzle from the contact point, the more likely it is that the jet will absolutely cut diagonally and become inconsistent.
Briefly describe the five benefits of waterjet cutting. No physical limits Waterjet cutting is a flexible process and can cut a wide variety of materials such as composites, plastics, various types of steel, glass, stone, ceramics, rubber, and even titanium and wheels.
By adding an abrasive (such as garnet), the waterjet machine can cut material up to 200 mm thick. No heat-affected zone
(HAZ) A major advantage of waterjet cutting is the absence of the heat-affected zone (HAZ) caused by the nature of cold cutting.
Cold cutting not only provides clean cuts but also ensures operator safety by eliminating thermal combustion factors. no physical distortion
At low temperatures, no heat exposure occurs in the material being cut. This process is especially important with materials such as steel, where clean cuts are obtained without material changes. The result is burr-free material and precise cuts. No additional finishing steps are required.
The precise results of this waterjet cutting process mean that the material does not have to undergo additional finishing operations. This process undoubtedly speeds up material production and leads to greater work efficiency.
No environmentally hazardous waste on a global scale, consideration of natural conditions and environmental pollution in various industrial fields is one of the axes. A significant advantage of waterjet cutting is that there is no contaminated waste formed as gas or smoke.
Is Pure Water Cutting and Abrasive Water Cutting Different? What’s the Difference between Both?
Pure water or often called (non-abrasive) cutting techniques are mainly used for cutting such soft materials like rubber, gaskets, foam, leather, textiles, and food. The water will be pressurized to very high levels and will be forced through tiny ruby or diamond orifices, forming a powerful stream of cutting. The stream of the jet travels up to 2.5 times equals to the sound, producing the ability to cut at extremely high feed rates and creating highly accurate and efficient cutting tools.
Abrasive water jet cutting: For such hard materials that can only be cut with water, replace the nozzle of water with such an abrasive cutting head. A high-velocity stream of water makes a vacuum that draws abrasives into the mixing chamber and creates a powerful, cohesive stream of the jet. This process is ideal for cutting any sheet or plate-shaped material, including mild steel, stainless steel, aluminium, sheet metal, decorative stone, engineering ceramics, and the glass.
Advantages of Cold Cutting
The cold-cutting process has many advantages, such as:
- It helps to improve material properties eliminating the hazards associated with hot cutting.
- Prevent heat-affected areas as there is no heat associated with it.
- Quick process.
- Eliminating the difficult and laborious manual milling process to create a weldable surface makes cold cutting very cost-effective.
- There is no chance of an explosion.
- No pollution from air, no spark, no flame.
- A temporary work permit is not required to begin work.
- Cold cuts are safer.
