Metal Stitching

Cast iron will only crack when it is stressed beyond its tensile strength. This includes all heat-related cracks, freeze cracks, impact and bending loads. Cast iron is a significantly durable metal that will not weaken over time, but still, it will change if exposed to high temperatures and prolonged stress over long periods of time. In-Situ offers a superior on-site crack repair process as part of our range of on site machining solutions.

Metal stitching (also known as a cold casting repair or metal locking) is a method of repairing cracks or fractures in all forms of cast metals, without the necessity to weld. Cast iron stitching is the most common form of repair as large cast iron components are one of the most challenging metals to repair by welding. This challenge is only made harder when trying to repair cast iron In-Situ, due to the requirements to preheat the component prior to welding.

Our metal stitching service conducted by expert engineers allows us to permanently repair a crack or replace a damaged casting section without welding. Instead, the crack or damaged area is either removed and replaced with a new section or stitched with specially designed stitching pins.

These stitching pins are inserted along the split line after a series of drilled and tapped holes are machined, exerting a radial pulling force and drawing the sides of the crack together. This results in a continuous row of interlocking stitching pins to create a robust, pressure-tight repair. Next, to add additional strength to the casting and repair, we install high tensile locks at 90 degrees 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, exerting a pulling force to provide additional strength.

Below are some images sharing our teams’ success in repairing cast iron components with metal stitching. Contact us with the enquiry form below if you have any questions about our metal stitching or other services.