1045 steel hardness rockwell

This experiment is attempted to measure the hardenability of the steel and understand the process of heat treatment of different materials at different cooling strategies. Cooling through different procedures will cause the materials to have different properties and different microstructures. Furthermore next stage of experiment relates the cooling rate and hardness of 1045 steel and 4143 steel. This also helps in determine how alloying a material permits it to be heat treated more homogeneously. Investigated results also proven to be close enough to expected results in obtaining higher brittleness with rapid cooling in and to improve ductility the process of tempering is proven to be very efficient with increase of tempering temperature the hardness of material must be decrease. Last but not least, after finishing experiment 6 the group found out that the lower the tempering temperature the lower the hardness. Also, the results that the group found from experiment 7 after finishing it proved being inconsistent from what it should be.

Introduction

The purpose of this experiment is to determine what effect heat treating and then cooling has on the hardness and grain structure of two different types of steel. The two different types of steels were utilized are 1045 steel samples and 4143 steel sample which is considered to be a low-alloy steel.

The heat-treating process is a method to alter physical and mechanical properties of the material. The heat-treating process is consists of three crucial steps of annealing, hardening, and tempering. Annealing is primarily used to soften and to induce the ductility of the specimens by heating and holding at suitable temperature and then cooling, by instantly quenching in the water, which produces the higher brittleness with low ductility and toughness in the specimens. Moreover, tempering is a process of heat-treating, which is used to increase the toughness of metal. Tempering is important because it used to achieve desired hardness. To restore some the toughness and impact properties is obtained by tempering where specimens are reheated to a temperature between 5000 F and 10000 F for certain time which removes the internal strain caused by sudden cooling in the quenching bath without a large decrease in hardness or strength.

In attempting the first phase of the experiment it cannot determined why some heat-treated materials don’t reach a high hardness when cooled at certain temperature. With the hardness test the hardness of a material can be determined. The Hardenability is a property that determines the depth and distribution of hardness when steel is heated to a given temperature and then quenched to reach martensitic structure, which is obtained by performing Jominy test, where an austenitized steel bar is quenched at one end only, thus producing a range of cooling rates along the bar.

Procedure

First of all, the experiment provided six 1045 steel specimens were for heat treating process, and for the second were only two steel rods of 1045 steel and 4143 steel respectively used to perform the Jominy test. In order to go though the details read the following: First the group begin with identifying all each specimen by punching different letter on to them using hammer. Second, the engineer students heated all specimens at 16000 F for 1/2 hour after obtaining the Rockwell a scale hardness measurement. Third, The four samples were quenched in water, one sample is allowed for air cool, and the other sample is set for furnace cool for one hour and quenched in water. Then, the two steel rods of different properties also allowed for heated at 16000 F for 45 minutes after obtaining the Rockwell scale hardness measurements. Also, the group measured the Rockwell a scale hardness on all six quenched specimens after being heat treated and tempered the three-quenched specimen at different temperature of 6000 F, 8000 F, and 10000 F respectively for 30 minutes. After tempering specimens then quenched in water. Moreover, obtained hardness measurements using Brinell (3000 kg) and Rockwell A scale on all six steel specimens. In order to perform the Jominy test one steel rod is then removed from the furnace and is placed in the cooling tower for 10 minutes before quenching in water, repeated the same procedure for other steel rod. Finally, measured the hardness 1/16 inch for the first inch and every 1/8 for the next inch and 1/4 for the next 2 inches using Rockwell a scale for both steel rods.