How to Install and Utilize Refractory Anchors
The proper installation and integrity of refractory anchors has a huge impact on the life and effectiveness of the refractory material they are being used for. Refractory materials are ones that maintain chemical and structural integrity at extreme temperatures and are therefore used in linings for things like home furnaces or incinerators. Because of the environments in which they are used, refractory materials must be able to withstand extreme thermal shock, be able to resist thermal expansion, and also be chemically inert in some cases. Refractory anchorage systems, such as wire anchors or sometimes ceramic tile anchors, must be able to support the weight of the refractory material at the same time as resisting the extreme conditions they are placed in. For the purpose of this demonstration we will use a wire anchoring technique for the purposes of an example.
Tools and Materials that You Will Need:
- Choose type and style of wire anchor
- Welding equipment
- Welding safety equipment
Step 1 - Choose the Correct Wire
The type and style of wire anchor you choose will relate directly to the exact job it will need to accomplish. The goal is for the wire anchor to securely hold the weight of the refractory material at the coolest temperature possible. The type of wire will depend on the temperature at which the system will operate it and the style of anchor will be determined by the particular job and placement. For example, for temperatures between 260 and 900 degrees C use a carbon steel. There should be a reference table available when purchasing your wire to help you decide on the right type of steel for your wire. As for type, an example would be that you are installing an anchor in an area that has moving parts. For this you may want to use an anchor of the appropriately rated steel that allows the wire to float in the attachment nut.
Step 2 - Install the Anchor at the Correct Length
The correct placement of refractory anchors should be so that the tips of the anchors are set at least 25 mm behind the hot face of the refractory material. You must also allow a small amount of space for the refractory anchors to expand with the extreme heat. It is suggested in some instructions to place a plastic tip over the ends of the anchors that will melt during heated use and allow the appropriate amount of space for the metal to expand.
Step 3 - Welding the Anchor in Place Properly
Welding the wire anchor tips securely in place is of extreme importance to the entire refractory system. Tack welding will not be sufficient. It is suggested that the welded tips of the refractory anchors should hold at least 15mm of weld fillet on each side. It is important to periodically check every 50 to 100 anchor welds as the installation process goes on by tapping with a hammer to be certain of the strength and integrity of the welds that you are doing.