Important technical terms

G 48 test
The G48 test is a corrosion test for the determination of resistance against pitting corrosion. First of all, the sample is carefully weighed, a surface determination is executed and afterwards the sample is boiled in a test solution for 24 hours. Subsequently, the weight is determined and the removal rate is calculated. Resistance against inter-crystalline corrosion is present, when the determined removal rate does not exceed a defined, critical limit value and the surface shows no pitting formation.

Gas tanker
Gas tankers are used for the transportation of natural gas. First of all, the natural oil extracted on the oil platform is cleaned, liquefied and by means of a tanker transported to the respective unload station (refineries). Gas tankers have a capacity of more than 125.000 m³ of natural gas.

Grain size
The grain size is either characterized by the mean diameter or the mean surface of the individual grain. The mean diameter of the grain normally lies between few m and several mm. The grain size is influenced by solidification, forming and thermal treatment processes. In that it has to be considered, that a grain basically has the tendency to grow, because due to that the energy of the grain boundaries tends to a minimum value. The properties of fine-grained materials are generally more favorable that those of coarse-grained ones.

Grinding
Procedure of the cutting shaping type for which the material removal (fine chips) is executed with the sharp edges of the grinding grains of the abrasive.