Heat Resistant Steel Alloys : Atlas Copco

Atlas Copco is interested in investigating the friction in the top-hammer drilling tool threads thatcauses the steel to heat up, leading to a phase transformation and a softer steel in the threads. Theaim of this project is to find a steel alloy or surface finishing that will retain its hardness atelevated temperatures better than the presently used threads material. The solution is intended tobe used as a replacement material for the threads. The potential material is meant to combat thepremature breakdowns of the threads and thus minimizing the economical losses. To achieve ourproject goal, literature studies and an experimental parts were employed.Hardening methods are discussed thoroughly in the thesis, such as carbides/nitrides,precipitation, solid solution, grain size, and martensitic transformation. Alloying elements andtheir effects on steels properties were also discussed. C, Cr, Co, Mn, Mo, Ni, W, and V werefound to increase the steel's hardness at elevated temperature, high temperature strength andabrasion wear resistance.Nitration can be applied to most of the steels that Atlas Copco uses today, and will give a harder,and more wear resistant surface at elevated temperatures. A problem with nitration is that thenitrided layer is generally thinner than the martensitic hardening used today.Three tool steels samples (ASP 2030, ASP 2053 and ASP 2060) were acquired from Erasteel.These were used in the experimental part and compared to reference steels that Atlas Copcocurrently are using (R1-R6). The experiments were conducted in 400 and 600°C and the sampleswere tempered for 1, 10 and 100 hours before the hardness were measured with a Vickershardness test. The conclusion from the experiments was that ASP 2060 and ASP 2053 fromErasteel are the steels that have a much higher hardness at elevated temperature than the othersteels tested in the experiment. The results indicate that the tool steels will probably notexperience the same premature breakdown as the threads used today. R1 and ASP 2053 have thegreatest heat resistance.The suggested tool steels are all quite expensive, and to minimize the material needed only thethreads and not the rod can be in the new alloy. Lowering the cost could also be achieved byhardfacing where a layer of the new expensive alloy is welded onto a cheaper steel

Heat Resistant Steel Alloys : Atlas Copco

Atlas Copco is interested in investigating the friction in the top-hammer drilling tool threads thatcauses the steel to heat up, leading to a phase transformation and a softer steel in the threads. Theaim of this project is to find a steel alloy or surface finishing that will retain its hardness atelevated temperatures better than the presently used threads material. The solution is intended tobe used as a replacement material for the threads. The potential material is meant to combat thepremature breakdowns of the threads and thus minimizing the economical losses. To achieve ourproject goal, literature studies and an experimental parts were employed.Hardening methods are discussed thoroughly in the thesis, such as carbides/nitrides,precipitation, solid solution, grain size, and martensitic transformation. Alloying elements andtheir effects on steels properties were also discussed. C, Cr, Co, Mn, Mo, Ni, W, and V werefound to increase the steel's hardness at elevated temperature, high temperature strength andabrasion wear resistance.Nitration can be applied to most of the steels that Atlas Copco uses today, and will give a harder,and more wear resistant surface at elevated temperatures. A problem with nitration is that thenitrided layer is generally thinner than the martensitic hardening used today.Three tool steels samples (ASP 2030, ASP 2053 and ASP 2060) were acquired from Erasteel.These were used in the experimental part and compared to reference steels that Atlas Copcocurrently are using (R1-R6). The experiments were conducted in 400 and 600°C and the sampleswere tempered for 1, 10 and 100 hours before the hardness were measured with a Vickershardness test. The conclusion from the experiments was that ASP 2060 and ASP 2053 fromErasteel are the steels that have a much higher hardness at elevated temperature than the othersteels tested in the experiment. The results indicate that the tool steels will probably notexperience the same premature breakdown as the threads used today. R1 and ASP 2053 have thegreatest heat resistance.The suggested tool steels are all quite expensive, and to minimize the material needed only thethreads and not the rod can be in the new alloy. Lowering the cost could also be achieved byhardfacing where a layer of the new expensive alloy is welded onto a cheaper steel

Heat Resistant Steel Alloys : Atlas Copco

Atlas Copco is interested in investigating the friction in the top-hammer drilling tool threads thatcauses the steel to heat up, leading to a phase transformation and a softer steel in the threads. Theaim of this project is to find a steel alloy or surface finishing that will retain its hardness atelevated temperatures better than the presently used threads material. The solution is intended tobe used as a replacement material for the threads. The potential material is meant to combat thepremature breakdowns of the threads and thus minimizing the economical losses. To achieve ourproject goal, literature studies and an experimental parts were employed.Hardening methods are discussed thoroughly in the thesis, such as carbides/nitrides,precipitation, solid solution, grain size, and martensitic transformation. Alloying elements andtheir effects on steels properties were also discussed. C, Cr, Co, Mn, Mo, Ni, W, and V werefound to increase the steel's hardness at elevated temperature, high temperature strength andabrasion wear resistance.Nitration can be applied to most of the steels that Atlas Copco uses today, and will give a harder,and more wear resistant surface at elevated temperatures. A problem with nitration is that thenitrided layer is generally thinner than the martensitic hardening used today.Three tool steels samples (ASP 2030, ASP 2053 and ASP 2060) were acquired from Erasteel.These were used in the experimental part and compared to reference steels that Atlas Copcocurrently are using (R1-R6). The experiments were conducted in 400 and 600°C and the sampleswere tempered for 1, 10 and 100 hours before the hardness were measured with a Vickershardness test. The conclusion from the experiments was that ASP 2060 and ASP 2053 fromErasteel are the steels that have a much higher hardness at elevated temperature than the othersteels tested in the experiment. The results indicate that the tool steels will probably notexperience the same premature breakdown as the threads used today. R1 and ASP 2053 have thegreatest heat resistance.The suggested tool steels are all quite expensive, and to minimize the material needed only thethreads and not the rod can be in the new alloy. Lowering the cost could also be achieved byhardfacing where a layer of the new expensive alloy is welded onto a cheaper steel

Optimization of Islet Microencapsulation with Thin Polymer Membranes for Long-Term Stability

Microencapsulation of islets can protect against immune reactions from the host immune system after transplantation. However, sufficient numbers of islets cannot be transplanted due to the increase of the size and total volume. Therefore, thin and stable polymer membranes are required for the microencapsulation. Here, we undertook the cell microencapsulation using poly(ethylene glycol)-conjugated phospholipid (PEG-lipid) and layer-by-layer membrane of multiple-arm PEG. In order to examine the membrane stability, we used different molecular weights of 4-arm PEG (10k, 20k and 40k)-Mal to examine the influence on the polymer membrane stability. We found that the polymer membrane made of 4-arm PEG(40k)-Mal showed the highest stability on the cell surface. Also, the polymer membrane did not disturb the insulin secretion from beta cells