The standard of high chromium alloy hammer production process

The standard of high chromium alloy hammer production process
One, material grade: KMTBCr20Mo
Two, chemical composition:
C% Si% Mn% S% P% Re%0.40-0.90 0.60-1.0 <0.05 <0.05 2.70-3.05 added 0.3
Mo% Ti% V% Cu% B% Cr%0.2-0.5 0.1-0.2 0.1-0.2 0.4-0.8 18-22 added 0.01
Three, commonly used raw materials:
High carbon ferrochrome: 60#, 65#; C = 4 - 10%;
High carbon ferromanganese: 70#, 75#; C = 3 - 7%;
Mo: 55#, 60#; C = 1%;Ti Fe: 30#, 40#; C = 0.1 - 0.3%;40#, 50#, 75#; C=0.3-1.0;20#, 25#; C=1.0-2.5%;Rare earth silicon 58,8 - 11,115: etc.;Si: 75#, C = 1.5%;
Copper: Cu = 99.99%;Carburizing agent: graphite electrode powder, C = 95%;
Scrap: ordinary carbon steel, alloy steel can jun;
Pig iron: low phosphorus iron impurities, Q10, Q12, Q16, z14, Z18, contain lead, tin can not add; bearing, file, high phosphorus cast iron, high silicon cast iron, silicon steel sheet, etc without or with less).
Four, smelting process:
1, first mixed with pig iron, scrap steel, iron three kinds of raw material of iron melt;
2, sampling and analysis of chemical composition;
3, continue to add a small amount of recycled material waiting for test results;
4, according to the test results to adjust the carbon content, and add back to the furnace full charge;
5, adding FERRO MOLYBDENUM, copper (molybdenum is difficult to melt, but also try to reduce the loss, so we must grasp the adding time; copper loss can join at any time)
6, while heating side in about 7 minutes before the addition of iron (vanadium; need to increase the adding of silicon ferrosilicon at this time)
7, before tapping 4-5 minutes added;
8, 3 - 5 minutes before tapping into aluminum, then adding titanium iron;
9, slag baked;
10, rare earth silicon placed at the bottom of the hanging bag, the impact of melting.
11, the molten iron sedation 3 - 2 minutes, began to pour.
Five, molding process:
Paint composition
1, refractory aggregate: quartz sand or corundum sand (when casting sand serious first layer with second layers of corundum sand, quartz sand);
2, carrier: water;
3, binder: white latex (organic)
4, suspension agent: sodium based bentonite, carboxymethyl cellulose;
In addition, according to the actual situation of production, the following materials are selected:
A/ penetrating agent, in order to enhance the coating on the foam surface wetting ability, improve coating;
B/ anti foam agent, in order to eliminate the bubbles in the paint, especially in the process of mixing barrel, but also need to eliminate bubbles;
C / preservatives, in order to prevent the deterioration of organic matter in water-based paint, aqueous solution of formaldehyde (formalin), Trichlorobenzene powder, pentachlorobenzene powder, sodium benzoate.
D/ active agent, in order to improve the flow of paint, such as adding baking soda powder.
Two) group box operation
(according to the actual situation of the production of flexible adjustment, into the molten iron principle is the bottom note type.)
Six, heat treatment process:
Quench hardening
Note: 1, the hammer flat on the trolley, to maintain a gap for ventilation and convection;
2, to 100 - 80 degrees C / h temperature to 600 degrees Celsius, heat insulation for 1 hours;
3, heat up to 900 degrees Celsius heat insulation for 0.5 hours;
4, heat up to 1020 degrees Celsius heat insulation for 3.5 hours;
5, heat up to 1050 degrees Celsius heat insulation for 0.5 hours, released strong wind cooling;
6, air cooled about 20 minutes after the casting surface, continue to cold to room temperature;
Two) tempering
1, installed furnace, heating to 300 - 3.5 degrees Celsius, thermal insulation 4 - 280 hours;
2, open the door, let the car stuck in the greenhouse in the natural cooling for 1 hours;
3, a car, parked in the car to hammer the natural air cooling.
Seven, physical performance index:
Hardness 58---63 HRC
The impact toughness of AK 5---8J/c square meters
Eight, metallographic structure:
Tempered martensite + carbide (above 30%) + retained austenite (a small amount)