Patents by Inventor Pavan CHALLA

Pavan CHALLA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240344166
    Abstract: A method for the fabrication of a resistance spot weld containing not more than two Liquid Metal Embrittlement cracks having a depth of 100 ?m or more, the method includes the following successive steps of providing at least two first zinc or zinc-alloy coated sheets having a first steel substrate of a first steel, with TS>900 MPa, a thickness of the zinc or zinc-alloy coated sheets being between 0.5 and 2.5 mm; measuring C1av(100), Si1av(100), Mn1av(100), Al1av(100), Cr1av(100), designating respectively the average content of C, Si, Mn, Al, Cr in the zone D100 of the first steel substrate comprised between 0 and 100 micrometers under the zinc or zinc-alloy coating; then calculating a factor CSI1 of the first steel CSI1=C1av(100)+(Si1av(100)/32)+(Mn1av(100)/14)?(Al1av(100)/48)+(Cr1av(100)/11) then; performing resistance spot welding on at least 10 welds with a certain intensity. A second steel sheet can be provided depending on measurements.
    Type: Application
    Filed: June 26, 2024
    Publication date: October 17, 2024
    Inventors: Jean-Marc PIPARD, Sebastien CREMEL, Anirban CHAKRABORTY, Damon PANAHI, Olga GIRINA, Hassan GHASSEMI-ARMAKI, Pavan CHALLA VENKATA SURYA, Yacine BENLATRECHE
  • Patent number: 12054802
    Abstract: A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 ?m or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×?), ? being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T?T1, so to obtain an atmosphere (A2) with a dew point DP2 between ?15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T1 up to a temperature T2 between 720° C. and 1000° C.
    Type: Grant
    Filed: May 10, 2023
    Date of Patent: August 6, 2024
    Assignee: ArcelorMittal
    Inventors: Jean-Marc Pipard, Sebastien Cremel, Anirban Chakraborty, Damon Panahi, Olga Girina, Hassan Ghassemi-Armaki, Pavan Challa Venkata Surya, Yacine Benlatreche
  • Publication number: 20230272502
    Abstract: A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 ?m or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×?), ? being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T?T1, so to obtain an atmosphere (A2) with a dew point DP2 between ?15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T1 up to a temperature T2 between 720° C. and 1000° C.
    Type: Application
    Filed: May 10, 2023
    Publication date: August 31, 2023
    Inventors: Jean-Marc PIPARD, Sebastien CREMEL, Anirban CHAKRABORTY, Damon PANAHI, Olga GIRINA, Hassan GHASSEMI-ARMAKI, Pavan CHALLA VENKATA SURYA, Yacine BENLATRECHE
  • Publication number: 20230257862
    Abstract: The present invention relates to a manufacturing method of a steel strip, a steel strip with controlled decarburized depth, a spot welded joint and the use of said steel strip or said spot welded joint. This invention is particularly well suited for the automotive industry due to the improvement of the Liquid Metal Embrittlement (LME) resistance along with target mechanical properties.
    Type: Application
    Filed: April 22, 2021
    Publication date: August 17, 2023
    Inventors: Ranbir Singh JAMWAL, Hassan GHASSEMI-ARMAKI, Anirban CHAKRABORTY, Pavan CHALLA VENKATASURYA
  • Patent number: 11649522
    Abstract: A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 ?m or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×?), ? being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T?T1, so to obtain an atmosphere (A2) with a dew point DP2 between ?15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T1 up to a temperature T2 between 720° C. and 1000° C.
    Type: Grant
    Filed: June 13, 2018
    Date of Patent: May 16, 2023
    Assignee: ArcelorMittal
    Inventors: Jean-Marc Pipard, Sebastien Cremel, Anirban Chakraborty, Damon Panahi, Olga Girina, Hassan Ghassemi-Armaki, Pavan Challa Venkata Surya, Yacine Benlatreche
  • Publication number: 20210004564
    Abstract: Method of tracking a plurality of objects comprising: focusing an image of the objects on an imaging element using an optical system; capturing the image of the objects using an imaging element comprising a plurality of pixels; measuring at least one characteristic of the objects from the captured image using an image processor; wherein the field of view is set be the widest field of view for which the image processor is able to measure the at least one characteristic.
    Type: Application
    Filed: March 7, 2019
    Publication date: January 7, 2021
    Inventors: Michele PERNI, Quentin PETER, Pavan CHALLA, Tadas KARTANAS, Pietro SORMANNI, Julius KIRKEGAARD, Michele VENDRUSCOLO, Chris DOBSON, Tuomas KNOWLES
  • Publication number: 20200181729
    Abstract: A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 ?m or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×?), ? being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T?T1, so to obtain an atmosphere (A2) with a dew point DP2 between ?15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T1 up to a temperature T2 between 720° C. and 1000° C.
    Type: Application
    Filed: June 13, 2018
    Publication date: June 11, 2020
    Inventors: Jean-Marc PIPARD, Sebastien CREMEL, Anirban CHAKRABORTY, Damon PANAHI, Olga GIRINA, Hassan GHASSEMI-ARMAKI, Pavan CHALLA VENKATA SURYA, Yacine BENLATRECHE