Box-type resistance furnace parameter setting method

1. Determination of furnace temperature

כאשר נעשה שימוש בחימום מהיר בתנור הקופסה, חיי השירות של חוט ההתנגדות נחשב. בדרך כלל, טמפרטורת התנור מוגדרת ל-920~940℃ (חוט ההתנגדות עשוי מחומר כרום-ניקל), 940~960℃ (חוט ההתנגדות עשוי מחומר ברזל-כרום-אלומיניום) או 960 ～980℃ (חוט ההתנגדות הוא חומר המכיל רכיבי סגסוגת כגון ניוביום ומוליבדן).

2. קביעת כמות התנור המותקן

The amount of furnace installed is generally determined according to the furnace power and use area. The principle is: the surface of the furnace wall of the first batch of workpieces has reached the specified temperature before the furnace is installed, and the furnace temperature can quickly return to the specified temperature after each installation. If the furnace load is too large and does not match the furnace power, the furnace temperature will not be restored for a long time, which will affect the correctness of the time calculation. In mass production, it can be “reduced into parts” and carried out continuously in batches.

3. Determination of heating time

The rapid heating time is generally calculated according to the effective size of the workpiece cross section, and determined according to the actual situation and past experience:

(1) The rapid heating time of a single piece can be calculated as follows:

t=ad

איפה t: זמן חימום מהיר (ים);

א: מקדם זמן חימום מהיר (s/mm);

d: The effective diameter or thickness of the workpiece (mm).

In the box-type resistance furnace, the effective diameter or thickness of the workpiece is less than 100mm, and the rapid heating time coefficient a is 25-30s/mm;

The effective diameter or thickness of the workpiece is greater than 100mm, and the rapid heating time coefficient a is 20-25s/mm.

Calculate the rapid heating time according to the above formula, which should be adjusted appropriately according to the determined furnace temperature and determined after passing the process verification.

(2) When parts are produced in batches, in addition to the calculation of the above formula, the rapid heating time should be added according to the installed furnace volume (m), the furnace density and the placement method:

When m＜1.5kg, no time is added;

כאשר m= 1.5 ~ 3.0 ק”ג, הוסף 15.30 שניות;

כאשר m=3.0 ~ 4.5 ק”ג, 30 ~ 40 שניות נוספות;

When m=4.5～6.0kg, add 40～55s.