Date: 11 August 2023

Optimising Machine Repair with Metal Stitching: Key Advantages

Many methods exist for repairing damaged machinery at your facility, including replacement, welding and brazing. However, these methods are fast being surpassed by the benefits of metal stitching. Read on to learn why metal stitching is an effective method for repairing metal cracks.

What Is Metal Stitching?

Metal Stitching is a mechanical crack repair process. It allows In-Situ to permanently repair a crack or without welding. The cracked metal is replaced with special metal stitching pins that are installed by drilling and tapping along the length of the crack together. This results in a continuous row of interlocking stitching pins to create a strong, pressure-tight repair. To restore the casting to its original strength, Locks are installed across the joint line of the pins by drilling a precision hole pattern with special drill fixtures. After the hole pattern is created, the locks are driven in, adding additional strength to the repair.

The repaired, metal-stitched area is gas and liquid tight to create a pressure-tight repair. In addition, metal stitching dampens and absorbs Compression Stresses. It also spreads tensile strains and distributes the load away from the original failure point while maintaining the alignment of the original surfaces.

This metal stitching method is employed mostly on cast iron components, but it is also effective on any other machinable metal, such as ductile iron, steel, aluminium and bronze castings.

The Dangers of Metal Cracks

Metal cracks are a critical issue that must be addressed to maintain safe working conditions. This statement is true for any facility, whether industrial, transport, marine repair or any other workplace that relies on large machinery.

These cracks may compromise the equipment's structural integrity, resulting in catastrophic failures and even fatalities or serious injuries. Additionally, damages can result in stress concentrations, potentially creating additional cracks forming and spreading from this initial one. Regarding marine environments, saltwater can accelerate the crack formation and increase metal component corrosion. Therefore, to guarantee workers' safety and the equipment's longevity, promptly identifying and repairing any cracks in metal machinery is essential. Metal cracks will be formed from various issues, such as contamination, stress, and sudden cooling.

These types of cracks in metal will compromise the strength of the weld, resulting in the breakdown of the machine or equipment, creating a health and safety risk and disrupting your planned daily operations. Furthermore, inadequately performed welding may result in additional cracks and potential issues in the future. Metal stitching is a highly effective solution to eliminating hazards such as these and has become a standard solution for many on-site machining repairs.

Cast Iron Graphitisation

Graphitisation is a type of corrosion that can occur in the cast iron components commonly used in various industries when exposed to high temperatures over an extended period. The carbon in the cast iron will separate from the iron, forming graphite. This weakens the cast iron, making it more susceptible to cracking and failure.

To provide a secure and high-quality result, our expert engineers monitor and assess the cracked area before determining what extra repair methods are required. This may include preheating the cast iron area to a specific temperature to stabilise the material and prevent further graphitisation.

Why Choose Metal Stitching Over Welding?

Metal stitching and welding are two different methods for repairing metal components such as cracked metal, but metal stitching is becoming increasingly popular for many reasons. We’ve already discussed how metal stitching works; however, welding involves heating the metal components to a specified pre-heat temperature and adding a filler material to join them.

Whilst welding used to be the popular repair solution, due to the versatility of metal stitching and the fact it is a cold casting repair, it has quickly been surpassed. Here are some critical differences between metal stitching and welding:

Maintaining Original Dimensions: Metal stitching allows for repairing cracks or breaks in metal components without significantly altering their original dimensions. In contrast, welding can often result in distortion or warping of the component, affecting its fit and function.

Increased Strength: Metal stitching creates a mechanical bond between the metal pins and the surrounding metal, often more potent than a welded joint. This is because the metal pins distribute the load across a wider area, reducing stress concentrations and increasing the strength of the repair.

Reduced Environmental Impact: Metal stitching does not require heat or consumables, such as filler material or shielding gas, which can harm the environment. In contrast, welding can produce hazardous fumes and waste products.

Whilst both of these repair methods have advantages and disadvantages making them suited to different roles, metal stitching is often preferred when the integrity of the cracked asset is a priority. However, it is worth noting that the stitching processes may be inadequate if the cracked area has suffered from extensive corrosion. This is why addressing cracks as soon as possible is vital to create a stronger result. In this instance, sections of the casting may need to be cut out to remove the damaged or corroded material and a new section stitched in place.

Metal Stitching at In-Situ Machining Solutions

At In-Situ Machining Solutions, our team conducts metal stitching as a reliable and permanent repair solution for cracks or damaged casting sections for various industries globally.

This method eliminates the need for welding and instead involves removing the damaged area, either replaced with a new section or repaired on-site to reduce repair expenses significantly. Our metal stitching processes will provide an effective and cost-efficient repair solution that minimises downtime and extends the lifespan of the equipment.

You can read about one of our many successes in our case studies, including our metal stitching repair on naval vessels.

Contact us to discover how our mobile, on site metal stitching services will help your business maintain productivity.

Case Studies

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