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Production method capable of preventing steel casting non-correlated magnetic mark display

A production method and a non-related technology, which are applied in the field of preventing non-related magnetic marks display of low carbon martensitic stainless steel weld fusion lines, can solve the problems of structure type or shape difference, difference, etc., to improve the quality of castings, and the effect is remarkable , the effect of reducing the difference in hardness

Inactive Publication Date: 2018-11-23
KOCEL STEEL
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In view of the above irrelevant magnetic marks, it has been proved by various tests that there are no unacceptable defects in the welded parts, and this phenomenon does not appear in all such material castings or all welded parts on a certain steel casting, but the irrelevant The presence of magnetic marks shows that the magnetism of the welding fusion line magnetic marks is quite different from that of the nearby base metal or weld meat, that is, the tissue type or shape is quite different; due to this difference, non-related magnetic marks show, Therefore, it is necessary to reduce this difference and further optimize the quality of steel castings. For this reason, it is necessary to invent a method to prevent the display of irrelevant magnetic marks on the weld fusion line

Method used

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Embodiment Construction

[0017] In order to illustrate the technical solution implemented by the present invention more clearly, the technical solution of the present invention will be further described below.

[0018] The present invention provides a production method for preventing irrelevant magnetic traces of steel castings, which is suitable for the prevention of non-relevant magnetic traces of low-carbon martensitic stainless steel weld fusion lines. The chemical composition of this type of material is mainly (mass percentage % ): C≤0.06, Si≤0.60, Mn: 0.40~1.50, P≤0.0040, S≤0.030, Cr: 11.5-14.0, Mo ≤1.0, Ni: 3.0-5.5, N≤0.020; main indicators of mechanical properties: resistance Tensile strength Rm≥750~780MPa, Rp0.2≥550~580MPa, elongation A≥18~20%, reduction of area Z≥50~55%, 0~20°C impact toughness Akv≥50~100J, body hardness 220 ~300HB.

[0019] A production method for preventing irrelevant magnetic marks from being displayed on steel castings, mainly comprising the following steps:

[0020] S...

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Abstract

The invention relates to a production method capable of preventing steel casting non-correlated magnetic mark display. The method comprises the steps that a welding material ingredient similar to a parent metal ingredient is selected as the welding material ingredient, and Nieq / Creq in the welding material ingredient is larger than or equal to 0.42; preheating before welding is carried out to preheat a defect and the portion within the scope of 200 mm-400 mm around the defect, and the temperature is 150 DEG C-200 DEG C; in the welding process, welding parameters corresponding to a welding material are controlled to be selected, and therefore the interlayer-temperature of a welding seam reaches 200 DEG C-300 DEG C; and the holding temperature of the heat treatment after welding is higher than or equal to 575 DEG C, and the holding time is longer than or equal to 7 h. By means of the method, the technological processes of a steel casting are not increased, the method is simple and practical, the maneuverability is high, and the obvious effect is obtained in the testing and actual volume production.

Description

technical field [0001] The invention relates to a production method for preventing the display of irrelevant magnetic traces of steel castings, especially suitable for preventing the display of irrelevant magnetic traces of the weld fusion line of low-carbon martensitic stainless steel, and belongs to the technical field of casting production. Background technique [0002] The present invention is mainly aimed at low-carbon martensitic stainless steel castings used in large-scale hydroelectric power plant units. Such steel castings generally consist of upper crowns, lower rings, blades and runner bodies combined by these castings. The materials of this kind of steel castings are generally ASTM A743 Grade CA-6NM and GX4CrNi13-4 in foreign countries, and ZG06Cr13Ni4Mo, ZG06Cr13Ni5Mo, ZG00Cr13Ni4Mo, ZG00Cr13Ni5Mo, ZG04Cr13Ni4Mo, ZG04Cr13Ni5Mo and other domestic brands. For low-carbon martensitic stainless steel castings, in order to avoid cavitation erosion and sediment wear in...

Claims

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Application Information

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IPC IPC(8): B23K9/00B23K9/23B23K9/235B23K35/30
CPCB23K9/0026B23K9/23B23K9/235B23K35/3086
Inventor 罗永建马进周辉黄敬
Owner KOCEL STEEL