How to Quickly Test the Spherical Quality of Wear-resistant Castings
First, the furnace before the test
Ball cast iron furnace before the test is an indispensable part of its production process, it is directly related to the quality of wear-resistant castings. Timely and accurate determination of the ball of iron liquid situation, you can quickly take measures to control the quality of wear-resistant castings. Misjudgment before the furnace will result in a large number of castings scrapped, waste modeling man-hour, so the furnace before the timely and accurate judgment of the ball than the furnace test is much more important. Actual production commonly used in the furnace before the test of iron liquid ballification of the following methods.
1, the surface crust and flames judge method
Rare earth magnesium wear-resistant castings containing low magnesium, and rare earth elements, iron surface and pure magnesium wear-resistant castings are not the same, the surface is not so much oxide, flames are not so much and powerful. But when the additional 1/3 iron liquid when the liquid will escape the light and white flames, shaped like candle. According to the number of flames, the height of the ball to determine the situation and magnesium residue, the higher the flames, the more powerful, that the ball good. Especially in the pouring, from the molten iron flow can be seen in the flames, such as the height of 25 ~ ffice: smarttags "/> 50mm, that is good ball; if the flames below 15mm, the ball is poor. Wear-resistant cast iron surface to see, the formation of oxide film, and silver-white rolling highlights, that is good for the ball, but the oxide film is too thick, then the liquid temperature is low.
2, triangular test block method
At present, by observing the test block to determine the spheroidization is a commonly used method. The mold used in the factory a lot of shapes, sizes vary, the majority of factories using triangular test block.
3, casting process to determine
(1) wear-resistant cast iron pouring into the mold, such as the pouring cup has been down to the concave, and the surface is very smooth, that the ball good; such as the upper part of the gate cup a layer of hard shell, Indicating that the molten iron temperature is low.
(2) During the pouring process, the sand-shaped surface splashing round flat iron beans with pitting (pits), indicating that the ball is good.
4, black border identification method
After the ball is finished, the sample spoon is poured into a test piece with a thickness of about 10mm. After cooling to dark red, after quenching, if there is a black side on the upper surface of the test piece, it means that the ball is bad and the thicker the black The worse, resulting in a recession, this time, such as iron liquid temperature can add additional alloy. From the test block can be seen: such as the test block around the arc-shaped, and the middle of the depression, and some also have a road wrinkles, it also means that the ball good; such as the test piece on the surface of the wheat-like point, then said Iron liquid oxidation, easy to decline. In this case, the furnace should be modified.
5, observe the solid state of molten iron
After the ballification treatment, remove a small amount of molten iron, pour into the Ф30mm cylindrical metal type, observed during the solidification of molten iron from the surface of the phenomenon of emission, and according to the amount of molten iron to determine the iron liquid ballification situation. The ball of good iron liquid, solid during the show a great expansion of the graphite, iron liquid surface in the beginning of the solidification of some decline in the surface after the shell there is a small amount of molten iron from the case of gushing; and spheroidized iron Surface emission is less.