Article image
Article image
This article displays in one automatically-generated column. View the full page to see article in its original form.


ADOPTED BY THE TRAMWAY BOARD. The Christchurch Tramway Board is at present adopting the thermit welding process, and will make a trial tomorrow morning. The process is entirely up-to-date, and Christchurch is the first place to adopt it in New Zealand. The thermit used for welding is in the .form of a powder, and consists of oxide of ironand aluminium, mixed in proper proportions. It is not explosive, and can be handled in safety. A heat, however, equal to melting steel is required to start the thermit, and this is done by placing a small quantity of igniting powder, which consists of powdered aluminium (bavium-superoxide) on the thermit, which ha 6 been placed in crucibles made from manganese ore. The igniting powder is set alight by a common match. The process is extreely simple. The ends and sides and top and bottom surfaces of the rails are properly cleaned. An. especially constructed clamp is attached to the rail, and so built as to pull the rail ends "close butted ;" the mould is then placed around the joint and well packed with moist sand, putty being used to protect the grooves from filling with thermit. The required quantity of thermit is then placed in the crucible and ignited by means of the bariumsuperoxide powder. In a few seconds the reaction is complete. The crucible will then contain at the bottom the molten steel covered with a lay«r of three times its volume, but equal weight of molten aluminium slag (corundum). This mass is po-ured into the mould. The corundum 6lag flows out before the steel touches the rails, depositing a layer around it and protecting the rail from contact with the molten thermit 6teel that follows. The thermit steel and corundum now surrounding the rails bring its butted joint to a welding heatwithin about twentyfive seconds. As soon as this takes place the clamps are drawn together, forcing the rails together, after which the welding heat gradually decreases and the weld is complete. A small amount of filing and cutting with cold setts is then necessary.

This article text was automatically generated and may include errors. View the full page to see article in its original form.
Permanent link to this item

Bibliographic details

NEW WELDING PROCESS., Star, Issue 8778, 15 November 1906

Word Count

NEW WELDING PROCESS. Star, Issue 8778, 15 November 1906

  1. New formats

    Papers Past now contains more than just newspapers. Use these links to navigate to other kinds of materials.

  2. Hierarchy

    These links will always show you how deep you are in the collection. Click them to get a broader view of the items you're currently viewing.

  3. Search

    Enter names, places, or other keywords that you're curious about here. We'll look for them in the fulltext of millions of articles.

  4. Search

    Browsed to an interesting page? Click here to search within the item you're currently viewing, or start a new search.

  5. Search facets

    Use these buttons to limit your searches to particular dates, titles, and more.

  6. View selection

    Switch between images of the original document and text transcriptions and outlines you can cut and paste.

  7. Tools

    Print, save, zoom in and more.

  8. Explore

    If you'd rather just browse through documents, click here to find titles and issues from particular dates and geographic regions.

  9. Need more help?

    The "Help" link will show you different tips for each page on the site, so click here often as you explore the site.