When PingFederate sends an artifact to your service provider (SP)'s SAML ACS endpoint or SAML 2.0 SLO endpoint, an element in the message indicates how long it should be considered valid. On the Artifact Lifetime tab, you can specify the expiry information in seconds.
You can change the default value to meet your requirements. You should also consider synchronizing your serve clock with your partner's SAML gateway server. If clocks are not synchronized, you might need to set the artifact lifetime to a higher value to prevent latency issues.