|Title of Invention||
A METHOD OF CALORISING STEEL PIPES/SECTIONS SURFACES
|Abstract||A method of calorising of pipes on steel section comprising the steps of: a. checking the dimensions and chemistry of the pipes based on the supplies test certificate, b. degreasing the said pipes using sodium hydroxide and potassium per magnate solution heated between 70 to 85 deg. c, c. water washing the degreased pipe twice at room temperature, d. picking the washed pipe using a light HCI solution, e. water washing the said pickled pipes twice, f. flux cleaning the thus pickled and washed pipe at 70 to 80 deg. c using a solution of KCI, NaCI, and ZnCI2. g. Dipping the said flux cleaned pipes in hot flux made of KCI, Na3AIF6, NaCI, and ZnCI2 for 6 minutes with the temperature of the bath being maintained between 740 to 770 deg c. h. Transferring the pipes within 6 minutes to molten aluminium - silicon bath containing 9 to 10% silicon at 760 to 790 deg c. i. Allowing the pipes to be in this bath for 6 to 8 minutes and removing the same after wiping the excess aluminium using air wipers. j. Cooling the said pipes and keeping ready for the diffusion process as enumerated further. k. Bundling the hot dip aluminium coated pipes and filling in to a retort, l. Evacuating the air within the retort with a vacuum pump, m. Lowering the retort a vertical furnace and starting the heating cycle, n. Allowing the hot air along with the residual moisture inside the retort to escape upto 125 to 130 deg c, o. Evacuating the residual air once again at this point and introducing nitrogen and maintaining a positive pressure of nitrogen, p. Heating the retort with the pipes further upto 560 to 570 deg c and maintaining the temperature at that point for 30 minutes, q. Subsequently raising the temperature upto 850 to 900 deg c, maintaining this temperature for 2 to 3 hrs and then cutting off the heating and cooling the retort with nitrogen to around 280 to 300 deg c within 1 to 1 1/2 hour, r. Removing the retort from the furnace and allowing it to cool naturally to room temperature before the pipes are unloaded. s. Immediately introducing a second retort which has been kept ready with the similarly aluminium coated pipes, during the heating of the first retort and on removal of the first retort in order to keep the process continuous. t. Further cleaning and straightening the pipes is done. u. Further a small section of the pipe is sectioned and checked in the laboratory for microstructure analysis, to determine the layer of the diffusion.|
|Full Text||FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
( Section 10)
A METHOD OF CALORISING OF STEEL SECTIONS AND THEREOF
SUNIL SHANTISARUP GUPTA
FLAT NO-l,3rd FLOOR,MITRA KUNJ
16, PEDDER ROAD, MUMBAI-400026
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION
This invention relates to a method of calorising of steel sections, particularly steel pipe.
This is a process where the aluminum is made to diffuse into the substrate of the pipe. The hot dip aluminum alloy coated pipes are bundled and filled into a retort. The air within the retort is evacuated with a vacuum pump. The retort is lowered into a vertical furnace and the heating cycle started. Upto 130 Deg C the hot air inside the retort is allowed to escape along with the residual moisture. At this point the residual air is once again evacuated and nitrogen is introduced. A positive pressure of nitrogen is maintained. The retort with the pipes is then further heated upto 570 Deg C and the temperature is maintained at that point for 30 minutes. Subsequently the temperature is raised to 950 Deg C. The total heating time is 3 hours. The temperature is maintained at 950 Deg. C for 2 hours. Then the heating is cut off and the retort is cooled with nitrogen to 300 Deg C within 1 hour. The retort is then removed from the furnace and let to cool naturally to room temperature before the pipes are unloaded.
In order to keep the process continuous a second retort which has been kept ready during the heating of the first retort is immediately introduced into the furnace on removal of the first retort.
Microphotographs of the microstructure are taken and the diffusion zone is checked for its depth and uniformity of penetration both on the inside and outside surfaces of the pipes. The pipes are cleaned and straightened. The edges are then prepared.
Similar diffusion of other non ferrous metals such as Chromium, Silicon and Boron can be done. The substrate can be Low carbon steel or alloy steel or stainless steel.
The non ferrous metals can be diffused individually or along with the others above named. Different combinations give different properties.
DATED THIS 12th DAY OF OCTOBER 2006
SUNIL SHANTISARUP GUPTA
(SIGNATURE OF APPLICANT)
|Indian Patent Application Number||1698/MUM/2006|
|PG Journal Number||8/2010|
|Date of Filing||16-Oct-2006|
|Name of Patentee||SUNIL SHANTISARUP GUPTA|
|Applicant Address||FLAT NO-1, 3RD FLOOR, MITRA KUNJ 16, PEDDER ROAD, MUMBAI 400026,|
|PCT International Classification Number||C23C10/58,10/00|
|PCT International Application Number||N/A|
|PCT International Filing date|