CN113308694B

CN113308694B - Titanium-nitrogen co-permeation process and hundred-year-old non-rotting pot for processing same

Info

Publication number: CN113308694B
Application number: CN202110735565.4A
Authority: CN
Inventors: 王文雄; 王绍锋; 谢泽华
Original assignee: Guangdong Murenking Appliance Co ltd
Current assignee: Guangdong Murenking Appliance Co ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-09-01
Anticipated expiration: 2041-06-30
Also published as: CN113308694A

Abstract

The application discloses a titanium-nitrogen co-permeation process and a hundred-year non-rotted pot for processing the same. Adopts a titanium nitrogen co-permeation process, and specifically comprises the following steps: titanium is coated on the inner surface of an iron pan, the thickness of the titanium layer is 130-550 mu m, nitrogen is introduced under the condition of air isolation, and titanium-nitrogen co-permeation treatment is carried out under the pressure of 8-12 Kg at the temperature of 700-1000 ℃. The alternating cold and hot titanium layers of the frying pan are not easy to fall off, the impurity heavy metal in the iron pan is sealed after titanium and nitrogen are co-penetrated, and the influence of the heavy metal on the health of a human body is reduced, so that the frying pan with the service life as long as one hundred years is obtained.

Description

Titanium-nitrogen co-permeation process and hundred-year-old non-rotting pot for processing same

Technical Field

The application relates to the field of cookers, in particular to a titanium-nitrogen co-permeation process and a hundred-year non-rotting pot for processing the same.

Background

The frying pan is generally divided into a stainless steel pan and an iron pan according to materials. The stainless steel pan has light and handy texture, can be easily stir-fried, can not stick cold oil of a cold pan, is particularly convenient for kitchen novice, and can not cause burnt and sticky bottom. However, the stainless steel pot can not hold the seasoning for a long time, and toxic substances in the stainless steel can be dissolved out by electrolyte of the seasoning, so that the long-term shovel is easy to wear. The iron pan releases iron element after resonance, and the iron element can be supplemented by frying in the iron pan. At high temperature, a small amount of iron element in the iron pan can infiltrate into food, so that the iron supplementing effect is achieved. But the iron pan is easy to rust, has unsmooth surface and loose structure and is easy to stick to the pan.

In order to process a durable and safe frying pan which supplements iron elements, an iron pan is generally taken as a base layer, titanium is plated on the surface of the iron pan, a plated part is cleaned, then the plated part is fixed in a vacuum furnace by a proper hanger, the vacuum furnace is heated to 200-500 ℃ in a high vacuum environment, and then an electron gun is used for heating solid raw material metallic titanium to melt, evaporate and ionize the metallic titanium, and finally the titanium plated part is deposited on the surface of raw iron to obtain the titanium plated iron pan.

In practice, the titanium-plated iron pan prepared by the method is repeatedly heated and cooled in the use process, and titanium is directly plated on the surface of the pan in the repeated heating and cooling process due to different expansion and contraction degrees of iron and titanium. Therefore, improvement is urgently required.

Disclosure of Invention

In order to manufacture a durable and safe frying pan capable of supplementing iron elements, the application provides a titanium-nitrogen co-permeation process and a one-hundred-year non-rotten frying pan processed by the same.

Firstly, the application provides a processing technology of a hundred-year non-rotting pan, which adopts a titanium-nitrogen co-permeation technology, and specifically comprises the following steps: titanium is coated on the inner surface of an iron pan, the thickness of the titanium layer is 130-550 mu m, nitrogen is introduced under the condition of isolating air, and titanium-nitrogen co-permeation treatment is carried out under the pressure of 8-12 Kg at the temperature of 700-1000 ℃.

Preferably, the pressure of the titanium nitrocarburizing is 10-12 Kg.

The strength of titanium is high, and the highest tensile strength of pure titanium can reach 180kg/m ² . Some steels have high strength as dry titanium alloys, but the specific strength (ratio of tensile strength to density) of titanium alloys exceeds that of high quality steels. The titanium alloy has good heat-resistant strength, low-temperature toughness and fracture toughness, so that the titanium alloy is widely used as aircraft engine parts and rocket and missile structural parts. Titanium alloys can also be used as fuel and oxidant tanks and high pressure vessels. Titanium alloys have been used to make white-step tests, mortar bed plates and the firing tubes of the backlashes. In the petroleum industry, it is mainly used as various containers, reactors, heat exchangers, distillation columns, pipes, pumps, valves, etc. Titanium can be used as a condenser for a pole and a power plant and as an environmental pollution control device. Titanium-nickel shape memory alloys have been widely used in instruments and meters. Titanium is used in medical treatment as an artificial bone and as various appliances. Having "space metal" in the shipbuilding industry, the chemical industry, the manufacture of mechanical parts, signaling equipment, hard compositesGold and the like have been increasingly used. Based on the above advantages, the inventors considered better application of titanium to the iron pan for improving the strength and durability of the iron pan.

Nitriding the titanizing iron pan under the conditions of 700-1000 ℃, 8-12 Kg pressure and air isolation, has strong nitrogen permeability, can enable titanium to permeate into deep layers from the surface of iron, is stably combined with pig iron, and is not easy to fall off when the titanium layers are repeatedly cooled and heated. The surface is smooth and has high hardness after long-time use. In addition, the impurity heavy metal in the iron pan is sealed after titanium nitrogen co-permeation, so that the heavy metal in the iron pan is difficult to separate out even after long-time use, and the influence of the heavy metal on human health is reduced, thereby obtaining a safe frying pan with a service life as long as one hundred years.

Preferably, gas nitriding is adopted in the titanium nitrocarburizing treatment.

Nitriding is a chemical heat treatment process for making nitrogen atoms permeate into the surface layer of an iron pan in a certain medium at a certain temperature. Liquid nitriding, gas nitriding, ion nitriding are common. The gas nitriding is to put the iron pan into a sealed container, let in flowing ammonia gas and heat, after keeping warm for a long time, the ammonia gas is thermally decomposed to generate active nitrogen atoms, which are continuously adsorbed to the surface of the iron pan and diffuse into the surface layer of the iron pan, thereby changing the chemical composition and the structure of the surface layer and obtaining excellent surface performance.

Nitrogen permeated into the iron forms iron nitride with different nitrogen contents with the iron from the outside to the inside, and combines with titanium element to form a titanium nitride layer, so that the titanium nitride has high hardness, thermal stability and high dispersity, and the nitrided steel piece can have high surface hardness and wear resistance.

The gas nitriding has strong comprehensive capability in terms of cost and effect, can fully contact with pig iron, so that nitriding treatment is more sufficient, a titanizing layer with stronger binding force with the pig iron is formed, the titanizing layer is not easy to fall off, and the service life of the frying pan is prolonged.

Preferably, the gas nitriding adopts a two-stage nitriding method, namely, the first stage is heat-preserving for 10 to 15 hours at the nitriding temperature of 700 to 800 ℃; and in the second stage, the temperature is increased to 800-900 ℃, and the temperature is kept for 20-25 hours, so that the titanium-nitrogen co-permeation treatment is completed.

The first stage is kept for 10-15 h, which is the nitrogen absorption stage. The lower ammonia decomposition rate is adopted at this stage, the surface of the iron pan is subjected to nitriding treatment after being cleaned, and the nitrogen concentration difference is formed between the surface and the inside. The second stage is diffusion stage, the nitriding temperature is raised to 800-900 deg.c to speed up the diffusion of nitrogen atom and raise ammonia decomposing rate, and the two-stage nitriding process has shorter treatment time than isothermal nitriding and shortened nitriding period.

Preferably, nitrogen removal treatment is carried out 2-3 hours before nitriding is finished, and the nitrogen removal temperature is increased to 900-1000 ℃.

The temperature is increased to carry out annealing treatment, so that the brittleness of the nitriding layer is reduced, and the fatigue resistance of the titanium nitride layer is further improved, and the titanium nitride layer is particularly difficult to deform after being used for a long time.

Preferably, the ammonia gas exchange rate of the first stage is 1-2 times/h, and the ammonia gas exchange rate of the second stage is 3-4 times/h.

When titanium nitrogen is co-doped, in order to maintain the prescribed ammonia decomposition rate, a proper amount of ammonia gas is continuously introduced to ensure that the nitriding speed is normal, and if the introduction of ammonia gas is stopped, the ammonia decomposition rate is higher and higher. The nitrogen potential of the furnace gas is too low, the state of the formed high-concentration titanium nitride layer on the surface of the iron cannot be continuously maintained, the nitriding speed is greatly reduced, but the diffusion capability to the inside is still realized due to the concentration difference of the diffusion layer. At the same time, the nitrogen concentration of the titanium nitride layer is also slowly reduced, the dense compound layer is crushed, and the ammonia decomposition rate and the speed of brushing the surface of the zero crossing member with fresh ammonia flow determine the nitriding capacity. By reasonably controlling the nitrogen introducing speed, the titanium nitride layer formed can be maintained under the titanium nitrogen co-permeation condition, and a firmer titanium plating layer is finally formed, so that the frying pan with longer service life is obtained.

Preferably, the surface of the iron pan is roughened to a roughness Ra of 30-60 mu m before titanium-nitrogen co-cementation.

The surface roughness of the iron pan is improved, the contact area of titanium and the iron pan is increased, the titanium is fully contacted with the surface of the iron pan, the titanium is firmly coated on the surface of the iron pan during thermal spraying treatment, and the titanium is easier to infiltrate into pig iron during titanium nitrocarburizing, so that the combination of the titanium and the iron is better, and the service life is further prolonged.

Secondly, the application provides a hundred-year non-rotting pot which is processed by the processing method and comprises a base layer made of iron, an iron nitride layer, an iron nitride-titanium nitride composite layer and a titanium nitride layer which are sequentially arranged in the direction away from the base layer, wherein the thickness of the iron nitride layer is 40-100 mu m, the thickness of the iron nitride-titanium nitride composite layer is 40-60 mu m, and the thickness of the titanium nitride layer is 100-500 mu m.

In conclusion, nitriding is carried out on the titaniferous iron pot under the conditions of 700-1000 ℃ and 8-12 Kg pressure and air isolation, so that the repeatedly cold and hot alternating titanium layers are not easy to fall off, impurity heavy metals in the iron pot are sealed after titanium and nitrogen co-permeation, the influence of the heavy metals on the health of a human body is reduced, and the frying pot with the service life as long as hundred years is obtained.

Detailed Description

Example 1

Step 1), titanizing: the inner surface of the pig iron pan was coated with titanium by arc thermal spraying, the thickness of the titanium layer being 130 μm.

Step 2), titanium nitrogen co-permeation treatment: placing the pig iron pot after titanium plating on a fixture, placing the pig iron pot with the pot mouth facing downwards into a nitriding furnace, and covering a cover. Introducing ammonia gas to enable the pressure to be 8Kg, enabling the ventilation rate of the ammonia gas to be 3 times/h, and preserving heat for 60h when the temperature in the furnace reaches 700 ℃; and then cooling the furnace, closing an ammonia gas channel when the temperature is reduced to 400 ℃, opening a nitrogen gas channel, and discharging the residual ammonia gas.

Step 3), surface treatment: taking out the treated iron pan, grinding and polishing the inner surface of the iron pan, removing the contamination on the inner surface, and filling the pores on the surface of the titanium nitride layer through thermal spraying treatment again to finally obtain the hundred-year non-rotten pan with the thickness of the iron nitride layer of 40 mu m, the thickness of the iron nitride-titanium nitride composite layer of 40 mu m and the thickness of the titanium nitride layer of 100 mu m.

Example 2

The embodiment discloses a hundred-year non-rotting pan, which is specifically processed by the following steps:

step 1), titanizing: the inner surface of the pig iron pan was titanium-plated by arc thermal spraying, and the thickness of the titanium layer was 550 μm.

Step 2), titanium nitrogen co-permeation treatment: placing the pig iron pot after titanium plating on a fixture, placing the pig iron pot with the pot mouth facing downwards into a nitriding furnace, and covering a cover. Introducing ammonia gas to ensure that the pressure is 12Kg, the ventilation rate of the ammonia gas is 3 times/h, and preserving heat for 50h when the temperature in the furnace reaches 1000 ℃; and then cooling the furnace, closing an ammonia gas channel when the temperature is reduced to 400 ℃, opening a nitrogen gas channel, and discharging the residual ammonia gas.

Step 3), surface treatment: taking out the treated iron pan, grinding and polishing the inner surface of the iron pan, removing the contamination on the inner surface, and filling the pores on the surface of the titanium nitride layer through thermal spraying treatment again to finally obtain the hundred-year-old non-rotten pan with the thickness of the iron nitride layer of 100 mu m, the thickness of the iron nitride-titanium nitride composite layer of 55 mu m and the thickness of the titanium nitride layer of 500 mu m.

Example 3

The difference compared with example 2 is that the pressure in step 2) is 10Kg, the thickness of the obtained iron nitride layer is 95 μm, the thickness of the iron nitride-titanium nitride composite layer is 60 μm, and the thickness of the titanium nitride layer is 500 μm

Example 4

The embodiment discloses a hundred years of non-rotted pot, and the difference with embodiment 3 is that:

step 2), titanium nitrogen co-permeation treatment: placing the pig iron pot after titanium plating on a fixture, placing the pig iron pot with the pot mouth facing downwards into a nitriding furnace, and covering a cover. The first stage: introducing ammonia gas to enable the pressure to be 8Kg, keeping the ammonia gas ventilation rate for 1 time/h, and keeping the temperature for 10 hours when the temperature in the furnace reaches 700 ℃; and a second stage: continuously heating to 800 ℃, preserving heat for 20 hours, and adjusting the ammonia ventilation rate for 3 times/h; continuously heating to 900 ℃, keeping the ammonia gas exchange rate for 0.5 times/h, preserving the heat for 2 hours, cooling the furnace, closing the ammonia gas channel when the temperature is reduced to 400 ℃, opening the nitrogen gas channel, and discharging the residual ammonia gas.

Example 5

step 2), titanium nitrogen co-permeation treatment: placing the pig iron pot after titanium plating on a fixture, placing the pig iron pot with the pot mouth facing downwards into a nitriding furnace, and covering a cover. The first stage: introducing ammonia gas to ensure that the pressure is 12Kg, the ventilation rate of the ammonia gas is 2 times/h, and preserving heat for 15h when the temperature in the furnace reaches 800 ℃; and a second stage: continuously heating to 900 ℃, preserving heat for 25 hours, and adjusting the ammonia ventilation rate for 4 times/h; continuously heating to 1000 ℃, keeping the ammonia gas exchange rate for 0.5 times/h, preserving the heat for 3 hours, cooling the furnace, closing the ammonia gas channel when the temperature is reduced to 400 ℃, opening the nitrogen gas channel, and discharging the residual ammonia gas.

Example 6

This example discloses a hundred years of unbreakable pan, and the difference with example 5 lies in:

before step 1), the inner surface of the pig iron pan is subjected to sand blasting treatment, and the roughness Ra reaches 30 mu m.

Example 7

before step 1), the inner surface of the pig iron pan is subjected to sand blasting treatment, and the roughness Ra reaches 60 mu m.

Comparative example

Comparative example 1

The difference from example 1 is that: the temperature in the furnace in step 2) was 600 ℃.

Comparative example 2

The difference from example 1 is that: the temperature in the furnace in step 2) was 1100 ℃.

Comparative example 3

The difference from example 1 is that: the pressure in the furnace in step 2) was 7Kg.

Comparative example 4

The difference from example 1 is that: the pressure in the furnace in step 2) was 13Kg.

Comparative example 5

The method comprises the steps of taking an iron pan as a base layer, cleaning the inner surface of the iron pan, fixing the iron pan in a vacuum furnace by using a proper hanger, heating to 400 ℃ in a high vacuum environment, heating solid raw material titanium by using an electron gun to melt, evaporate and ionize the solid raw material titanium, and finally depositing the solid raw material titanium on the surface of raw iron to obtain the titanium-plated iron pan.

Performance detection for pot without rotting for century

Test 1 hardness test

According to GB/T230.1-2009 "Rockwell hardness test of Metal Material", the frying pans of examples 1-7 and comparative examples 1-5 were subjected to hardness testing before use and after 360 ten-thousand simulated stir-frying, respectively designated as H1 and H2, using a Rockwell hardness tester of type HR-150D.

The specific detection results are shown in Table 1.

Test 2 heavy metal test

Detection of heavy metal ions in frying pans of examples 1 to 7 and comparative examples 1 to 5: the pot was used to cook water, here deionized water, for 24 hours, and then the heavy metal content in the water was measured as the precipitation A1.

Heavy metal ions were detected after 360 ten thousand times of simulated stir-frying in the frying pans of examples 1 to 7 and comparative examples 1 to 5: the pot was used to cook water, here deionized water, for 24 hours, and then the heavy metal content in the water was measured as the precipitation A2.

The specific detection results are shown in Table 3.

The detection method comprises the following steps:

determining two heavy metal elements Pb and Cd by adopting a heavy metal rapid detector of Guangdong Dana oasis food safety technology and technology Co., ltd; measuring Cr element by adopting a dibenzoyl dihydrazide spectrophotometry; and measuring the Ni element by adopting a flame atomic absorption spectrophotometry.

The national standard GB/T4806.9-2016 "food safety national standard Metal Material for food contact and products", wherein the dissolution of heavy metal harmful substances such as Pb, cr, cd, ni is limited, and the specific reference can be seen in Table 2.

Table 1 hardness test

Project	H1/HRC	H2/HRC
			Example 1	62	60
Example 2	65	63
			Example 3	64	63
Example 4	66	64
			Example 5	65	63
Example 6	67	66
			Example 7	68	67
Comparative example 1	58	50
			Comparative example 2	57	50
Comparative example 3	59	52
			Comparative example 4	57	51
Comparative example 5	55	47

Table 2 Standard requirements for elution amount of heavy metal hazardous substances such as Pb, cr, cd, ni from stainless steel tableware container.

TABLE 3 heavy metal detection data

According to the comparison of the data of the examples 1-2 and the comparative examples 1-5, the hardness of the examples 1-2 is higher than that of the comparative examples 1-5, the heavy metal content before simulation of the examples 1-2 and the heavy metal content after simulation of 360 ten thousand times are smaller than that of the comparative examples 1-5 and are in a standard range, the examples are continuously used for 100 years under the condition that the shovel 100 is used every day for 360 ten thousand times, and the simulated stir-frying experiment is completed for up to 42 days. The application shows that the titanizing (130-500 mu m titanizing layer) iron pan is nitrided under the conditions of 700-1000 ℃ and 8-12 Kg pressure and air isolation, so that the repeated cold and hot alternating titanium layer of the frying pan is not easy to fall off, the impurity heavy metal in the iron pan is sealed after the titanium and nitrogen are co-permeated, the influence of the heavy metal on the human health is reduced, and the frying pan with the service life as long as hundred years is obtained.

Claims

1. A processing technology of a hundred-year-old non-rotten pan is characterized in that: adopts a titanium nitrogen co-permeation process, and specifically comprises the following steps: coating titanium on the inner surface of an iron pan, wherein the thickness of the titanium layer is 130-550 mu m, introducing nitrogen under the condition of air isolation, and performing a two-stage nitriding method under the pressure of 8-12 Kg, namely preserving heat for 10-15 h at the nitriding temperature of 700-800 ℃ in the first stage; in the second stage, the temperature is increased to 800-900 ℃, and the temperature is kept for 20-25 h, so that the titanium-nitrogen co-permeation treatment is completed; nitrogen removal treatment is carried out 2-3 hours before nitriding is finished, and the nitrogen removal temperature is increased to 900-1000 ℃; the ammonia gas exchange rate of the first stage is 1-2 times/h, and the ammonia gas exchange rate of the second stage is 3-4 times/h; before titanium-nitrogen co-permeation, firstly carrying out rough treatment on the surface of the iron pan to ensure that the roughness Ra reaches 30-60 mu m.

2. A processing technology of a hundred-year-old non-rotten pan is characterized in that: the processing technology of claim 1 is used for processing the steel plate, and the steel plate is formed by processing a base layer made of iron, wherein an iron nitride layer, an iron nitride-titanium nitride composite layer and a titanium nitride layer are sequentially arranged in the direction away from the base layer, the thickness of the iron nitride layer is 40-100 mu m, the thickness of the iron nitride-titanium nitride composite layer is 40-60 mu m, and the thickness of the titanium nitride layer is 100-500 mu m.