Problem Solving

Machine Shops

The primary service provided for machine shops is analysis and identification of base alloys to allow proper selection of weld filler materials and weld repair procedures.

This can be difficult because in some cases the surface to be repaired has already been welded and the elemental content is a mixture of one or more alloys. Additionally, DIN specifications are involved with offshore suppliers and a comparative SAE alloy must be selected. Approximately 100+ such determinations are performed annually.

Additional services include hardness measurements to determine whether heat-treatment was correct. Touchstone has also performed many failure analyses for this industry and helped to solve many manufacturing problems.

The following examples illustrate some of our contributions to this business sector:

  • The failure of two, D7 tool steel punches was brought to the attention of Touchstone Engineers. The fracture surface clearly indicated brittle fracture and the problem was traced to incomplete tempering in the manufacture of the punch. Tool steels are often double or triple tempered to improve toughness, and the microstructure of this material indicated that additional tempering was required.
  • A cutting compound effluent sample was evaluated to determine whether treatment with a flocculant was effective. The flocculant was designed to remove suspended material prior to pruification of the coolant water. The method was found to be effective, but careful use of reagents was required.
  • A machine shop requested that hardness tests be performed on nine samples. The samples were provided after machining and heat treatment to determine whether the proper hardness was attained. Findings indicated that only four of nine had reached the proper hardness. While this necessitated additional heat treatment, the hardness determinations prevented substandard material from reaching the user.
  • Touchstone was asked to perform the following determinations chemical and mechanical analysis and to determine the reason for failure of the an iron plunger. TRL concluded that the failure was caused by: the presence of gas porosity in weld filler material used to rebuild the part, the lack of any radius at the fracture point, and the presence of brittle martensite in fusion zone where the stainless filler material was applied.
  • A 2″ diameter pin was investigated to determine the cause of lower hardness after flame hardening. TRL concluded that the hardness and the microstructure was consistent with the presence of a decarburized layer in the softer areas.

The above examples are only a sample of our work in this area. We would be pleased to provide any additional information you may require. We also invite you to review examples on our website of work that we have performed in support of other business sectors.