Working With Boron-Alloyed Steel - Identification

OEM repair information is the best source to identify if a part is UHSS.

Knowing whether or not a part is made of boron-alloyed steel is important for repairs and replacement. OEM repair information is the best source to identify if a part is UHSS.decisions. The location of the part can be used to determine if the part is likely to be an ultra-high-strength steel (UHSS) part. However, part location is not definitive, the part could be boron-alloyed steel or it could be a part that is below 600MPa steel. The location will help to prompt further research into straightening, sectioning, or replacing at factory seams. Steel identification may also help determine removal and attachment methods.

The vehicle maker service information is the most accurate source for identifying steel strength and possible repairs. A hardness tester will give a reading, but the technician then has to make repair and replace decisions based on knowledge learned through training and experience.

Other ways to identify steel strength include the drilling test and the cutting test. These tests will only give the technician a general idea of the strength of the steel help prevent repairs from causing damage to the vehicle. The results of the test may also confirm the suspicion that the steel is in the higher strength range and that it should be treated as high-strength steel (HSS) or UHSS.

To perform the drilling test, drill a spot weld with a standard spot weld drill bit at high speed, above 1000 rpm. If the metal burns the bit on one spot weld, it is most likely UHSS. If, however, the drill bit drills three to five spot welds, it may still be UHSS, but at the mid- to lower-strength range of UHSS.

This drill bit was burnt before making one hole through an UHSS part.When performing the cutting test, if the damaged part cannot be cut with a standard air saw blade, it may be UHSS. If the teeth are removed from the saw blade after a short cutting time, the part is most likely made of UHSS. Please note that some saw blades are designed for higher strength steel and should not be used for this test.

14343The QMT 1000 hardness tester is used to test the MPa rating of a panel.

14342-burntThis drill bit was burnt before drilling one hole on an UHSS part.

14344The teeth were flattened and unable to cut into an UHSS part.

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