What can cause a heating element to deform this way? My oven is tripping the breaker whenever I turn on the heating, LCD and light are working fine, the front LED flickers though! The model of the oven is IKEA Framdit OV9. One of the elements has 30 ohm resistance and the other has 60, and given the data on the elements they have 1650 and 800 Watts power rating respectively. So for 230v they resistance seems be fine.
What can cause a heating element to deform this way?
Metal expands when it gets hot. This means that this ~2 Meter heating strip becomes ~25mm longer per 100 degree rise in temperature.
When you have a steel tube fixed in two points and make it longer by heating it, something must give. Either the mounting must allow the expansion or the tube will bend.
These steel tubes contain heat conducting ceramic sand an a resistive wire for that carries the heating current. This wire is coiled to allow for bending and expansion.
However, when the bending radius is too tight, or a thermal cycling pumping effect moves the sand away, you will get a short circuit.
However, since everything expands and contracts by heat the short may not become noticeable until the heater gets to a certain temperature.
When designing mounting for heaters like this there may only be one rigid point. All other mounts must allow for sliding or other movement to give room to the expansion. (the clicking noises in your oven)
The reason for this element to fail is probably the horizontal mounting bar in the middle. It provided too much rigidity causing the element to buckle.