US2025188577A1PendingUtilityA1

Iron casting and method of manufacturing it

Assignee: HINODE LTDPriority: Mar 14, 2022Filed: Mar 13, 2023Published: Jun 12, 2025

Est. expiryMar 14, 2042(~15.7 yrs left)· nominal 20-yr term from priority

Inventors:Takuo Umetani

C21D 8/00C21D 5/00C22C 37/10C21D 2211/001C21D 2201/00C21D 1/84C21D 1/26C21D 6/008C21D 6/007C21D 6/001C22C 37/04

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Claims

Abstract

A method of manufacturing an iron casting by executing a heat treatment for a heat treatment object that is provided by using and casting an austenite-type material for casting is provided. The heat treatment includes a first holding step of holding the heat treatment object at a first holding temperature of 850° C. or higher and 1250° C. or lower, and a first cooling step of cooling the heat treatment object to a first cooling end temperature of −150° C. or higher and 150° C. or lower after the first holding step. The first holding step includes holding the heat treatment object for a first holding time of 0.25 hours or more and 100 hours or less.

Claims

exact text as granted — not AI-modified

1 . A method of manufacturing an iron casting by executing a heat treatment for a heat treatment object that is provided by using and casting an austenite-type material for casting, wherein
 the material for casting includes 26.0 mass % or more and 50.0 mass % or less of Ni, 0.1 mass % or more and 3.5 mass % or less of C, 0.1 mass % or more and 3.5 mass % or less of Si, 0 mass % or more and 8.0 mass % or less of Co, 0 mass % or more and 3.0 mass % or less of Mn, 0 mass % or more and 0.2 mass % or less of Mg, and a balance that is Fe and an inevitable element(s),   the heat treatment includes
 a first holding step of holding the heat treatment object at a first holding temperature of 850° C. or higher and 1250° C. or lower, and 
 a first cooling step of cooling the heat treatment object to a first cooling end temperature of −150° C. or higher and 150° C. or lower after the first holding step, and 
   the first holding step includes holding the heat treatment object for a first holding time of 0.25 hours or more and 100 hours or less.   
     
     
         2 . The method according to  claim 1 , wherein
 the first cooling step includes cooling the heat treatment object at a first cooling rate of 0.01° C./min or higher and 300° C./min or lower.   
     
     
         3 . (canceled) 
     
     
         4 . The method according to  claim 1 , wherein
 the first holding time is 2.5 hours or more and 25 hours or less.   
     
     
         5 . The method according to  claim 1 , wherein
 the first cooling end temperature is 0° C. or higher and 100° C. or lower.   
     
     
         6 . The method according to  claim 1 , wherein
 the first cooling step includes
 a primary cooling step of cooling the heat treatment object at a primary cooling rate, and 
 a secondary cooling step of cooling the heat treatment object at a secondary cooling rate that is higher than the primary cooling rate after the primary cooling step, 
   the primary cooling step includes cooling the heat treatment object to a primary cooling end temperature of 250° C. or higher and 950° C. or lower, and   the secondary cooling step includes cooling the heat treatment object to the first cooling end temperature.   
     
     
         7 . The method according to  claim 6 , wherein
 the primary cooling rate is 0.01° C./min or higher and 20° C./min or lower, and   the secondary cooling rate is 1° C./min or higher and 40000° C./min or lower.   
     
     
         8 . (canceled) 
     
     
         9 . The method according to  claim 6 , wherein
 the first holding time is 2.5 hours or more and 25 hours or less.   
     
     
         10 . The method according to  claim 6 , wherein
 the primary cooling end temperature is 450° C. or higher and 850° C. or lower.   
     
     
         11 . The method according to  claim 6 , wherein
 the first cooling end temperature is 0° C. or higher and 100° C. or lower.   
     
     
         12 . The method according to  claim 1 , wherein
 the heat treatment further includes
 a second holding step of holding the heat treatment object at a second holding temperature of 250° C. or higher and 950° C. or lower after the first cooling step, and 
 a second cooling step of cooling the heat treatment object to a second cooling end temperature of −150° C. or higher and 150° C. or lower after the second holding step, and 
   the second holding step includes holding the heat treatment object for a second holding time of 0.25 hours or more and 25 hours or less.   
     
     
         13 . The method according to  claim 12 , wherein
 the first cooling step includes cooling the heat treatment object at a first cooling rate of 0.01° C./min or higher and 300° C./min or lower.   
     
     
         14 . (canceled) 
     
     
         15 . The method according to  claim 12 , wherein
 the second cooling step includes cooling the heat treatment object at a second cooling rate of 1° C./min or higher and 40000° C./min or lower.   
     
     
         16 . (canceled) 
     
     
         17 . The method according to  claim 12 , wherein
 the first holding time is 2.5 hours or more and 25 hours or less.   
     
     
         18 . The method according to  claim 12 , wherein
 the first cooling end temperature is 0° C. or higher and 100° C. or lower.   
     
     
         19 . The method according to  claim 12 , wherein
 the second holding temperature is 550° C. or higher and 950° C. or lower.   
     
     
         20 . The method according to  claim 12 , wherein
 the second cooling end temperature is 0° C. or higher and 50° C. or lower.   
     
     
         21 .- 23 . (canceled) 
     
     
         24 . A method of manufacturing an iron casting by executing a heat treatment for a heat treatment object that is provided by using and casting an austenite-type material for casting, wherein
 the heat treatment includes
 a first holding step of holding the heat treatment object at a first holding temperature of 850° C. or higher and 1250° C. or lower, and 
 a first cooling step of cooling the heat treatment object to a first cooling end temperature of −150° C. or higher and 150° C. or lower after the first holding step, and 
   the first holding step includes holding the heat treatment object for a first holding time of 0.25 hours or more and 100 hours or less.   
     
     
         25 . The method according to  claim 24 , wherein
 the first cooling step includes
 a primary cooling step of cooling the heat treatment object at a primary cooling rate, and 
 a secondary cooling step of cooling the heat treatment object at a secondary cooling rate that is higher than the primary cooling rate after the primary cooling step, 
   the primary cooling step includes cooling the heat treatment object to a primary cooling end temperature of 250° C. or higher and 950° C. or lower, and   the secondary cooling step includes cooling the heat treatment object to the first cooling end temperature.   
     
     
         26 . The method according to  claim 24 , wherein
 the heat treatment further includes
 a second holding step of holding the heat treatment object at a second holding temperature of 250° C. or higher and 950° C. or lower after the first cooling step, and 
 a second cooling step of cooling the heat treatment object to a second cooling end temperature of −150° C. or higher and 150° C. or lower after the second holding step, and 
   the second holding step includes holding the heat treatment object for a second holding time of 0.25 hours or more and 25 hours or less.   
     
     
         27 . An iron casting that is manufactured by using the method according to  claim 1 .

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