ABSTRACT

The study investigated the quenching of mild steel using Banana Pseudostem Sap (BPS). Six samples of mild steel were used in this investigation - two were quenched in air, three were quenched in BPS and one remained unquenched. A Rockwell hardness testing machine was used to test for the hardness of the five samples that were quenched in air and BPS. The result of the hardness test showed that the BPS quenched steel had higher hardness values of 83 HRB, 86 HRB and 84 HRB as against the air quenched samples which had 75.7 HRB and 76.3 HRB as the average hardness values. The unquenched sample had a value of 72 HRB. The corrosion tests carried out on a 4-day interval on all the samples showed that mild steel quenched in BPS is less susceptible to corrosion than the air quenched and untreated samples. The corrosion rates of 7.896mmpy, 8.538mmpy and 5.11ommpy were gotten from the unquenched, air-quenched and BPS-quenched samples respectively at the first interval. Values of 3.056mmpy, 3.352mmpy and 1.951mmpy were obtained at the third interval. 1.85 lmmpy, 2.03 8mmpy and 1.206mmpy were finally obtained at the 6th interval (24th day). Itwas observed that as soaking time reduces at a steady austenising temperature, the average value of hardness increases. It was also discovered that the relationship between austenising temperature and soaking time affects the hardness of the quenched mild steel samples. Since the BPS quenched mild steel has a higher hardness value, it is more suitable to make power shovels, steel balls, nozzles, crusher and plates for rock processing.