Magnetic permeating pot with flower-shaped hot-forged bottom covering piece and production method thereof

Abstract

A magnetic permeating pot with a flower-shaped hot-forged bottom covering piece and a production method thereof belong to the technical field of aluminum pots. The magnetic permeating pot structurally comprises an aluminum alloy pot body and a steel bottom covering piece, the steel bottom covering piece has a flower-shaped structure and is embedded into the bottom surface of the aluminum alloy pot body and keeps flat with the bottom surface of the aluminum alloy pot body, and expansion buffer strips are formed on portions, extending out of the steel bottom covering piece, of the aluminum alloy pot body. The production method includes embedding the steel bottom covering piece into the bottom surface of the aluminum alloy pot body by hot forging. Compared with the prior art, the magnetic permeating pot with the flower-shaped hot-forged bottom covering piece has the advantages that firstly, relative difference of variation of expansion caused by heat and contraction caused by cold between the aluminum alloy pot body and the bottom covering piece can be reduced greatly; secondly, the defect of middle arch of the integral stainless steel bottom covering piece can be eliminated completely; thirdly, noise caused by magnetic lag can be lowered evidently; fourthly, skin effect of induction current can be improved greatly; and fifthly, the flower-shaped hot-forged bottom covering piece is firmer, flatter, more energy-saving and more effective as compared with the bottom covering piece in the prior art.

Description

technical field [0001] The invention belongs to the technical field of aluminum pots, and in particular relates to an electromagnetic pot with a flower-shaped hot forging and pressing bottom sheet and a production method thereof. Background technique [0002] As a household tableware, the induction cooker is widely welcomed because of its convenience, but since there are only three elements with magnetic permeability known in nature, iron, cobalt and nickel, obviously, cobalt and nickel are relatively rare elements on the earth Not to mention the high price, and it may have adverse effects on the human body, only iron is a large, cheap and harmless material, but the cast iron pot that has been used for thousands of years has a disadvantage, that is, it is easy to rust; alloy steel such as Because stainless steel contains a lot of chromium elements, it has been proved that it is harmful to health. Moreover, stainless steel has high strength and hardness, and it is difficult t...

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Problems solved by technology

[0002] As a household tableware, the induction cooker is widely welcomed because of its convenience, but since there are only three elements with magnetic permeability known in nature, iron, cobalt and nickel, obviously, cobalt and nickel are relatively rare elements on the earth Not to mention the high price, and it may have adverse effects on the human body, only iron is a large, cheap and harmless material, but the cast iron pot that has been used for thousands of years has a disadvantage, that is, it is easy to rust; alloy steel such as Because stainless steel contains a lot of chromium elements, it has been proved that it is harmful to health. Moreover, stainless steel has high strength and hardness, and it is difficult to draw, deform and polish. Therefore, aluminum alloys with large quantities, low prices and easy processing are widely used in the pot making industry. However, the general aluminum alloy is not magnetically conductive and cannot be heated by an induction cooker, so a non-austenitic stainless steel aluminum alloy pan with a negative film was invented.

The earliest stainless-steel-covered aluminum alloy pots used a welding structure. This welding process was extremely difficult and the fastness was extremely poor. Later, someone invented a riveting connection structure instead. Although the riveting connection is inferior to the original welding process However, there are still many deficiencies. For example, the Chinese Patent Publication No. ZL200510050623.0, an invention patent titled "a composite pot bottom of an aluminum pot", discloses a composite pot bottom, which is placed on the bottom of an aluminum pot bottom. The upper steel plate is compositely fixed, and a plurality of raised parts are preformed on the bottom of the pot bottom, and a plurality of turning holes matching the raised parts are punched out on the surface of the steel plate, and the steel plate is attached to the aluminum pot On the bottom of the bottom, make the turning hole card of the steel plate fit on the raised part of the bottom of the pot, and at the same time insert the turning edge around the turning hole into the bottom of the pot bottom, and deform the raised part to cover the turning bottom on the curved surface, and the steel plate is compositely fixed on the bottom of the aluminum pot

This double-bottom pot has the same feature as other similar pots in the prior art, that is, the stainless steel plate used for the double bottom is cold-pressed on the bottom of the aluminum pot as a whole, and the pot body combined in this way has the following disadvantages First, because the linear expansion coefficients of aluminum and steel are almost twice the difference, when the steel plate with a larger area is heated to above 300°C, the length of the aluminum alloy pan body and the stainless steel plate will be at a position farther from the center. The difference in area change is very large, which is very easy to cause damage to the joint between the riveted aluminum alloy pot body and the steel plate, and the stainless steel plate will loosen or even fall off from the pot body due to repeated thermal expansion and contraction during repeated use; Second, due to the obvious differences in the changes in the absorbed power heating of various parts of the large-area steel plate, theoretical calculations show that during induction heating, 86.5% of the power is converted into heat energy in the current penetration depth layer, while the current penetration The strength decays very quickly along the depth of the steel plate, which will inevitably cause the lower surface of the steel plate to be heated more than the upper surface, and the elongation changes greatly. The internal stress and residual stress caused by this elongation difference will cause the bottom of the pot to bow downward. It even far exceeds the requirement of 3 / 1000 stipulated in the standard; third, the noise caused by the magnetic hysteresis of the steel plate of the overall structure is obvious, causing environmental pollution, and the noise consumes energy, which does not meet the energy-saving requirements; fourth, due to the alternating magnetic field The induced current has a skin effect, and its distribution is a negative exponential function. The induced current is seriously unevenly distributed from the outside to the inside of the steel plate of the overall structure. Small, very low induction heating effect

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